Factors Influencing Compensation of Early Career Neonatologists.

OBJECTIVE: Workforce characteristics and compensation specific to early career neonatologists remain poorly defined. Lack of transparency surrounding compensation limits benchmarking for neonatologists entering the workforce and may negatively influence individual lifetime earnings. Our objective was to provide granular data for this unique subpopulation by defining employment characteristics and factors influential to compensation of early career neonatologists. STUDY DESIGN: An anonymous 59-question cross-sectional electronic survey was distributed to eligible members of American Academy of Pediatrics Trainees and Early Career Neonatologists. A focused analysis was conducted on salary and bonus compensation data collected from the survey instrument. Respondents were classified based on primary site of employment: nonuniversity located (e.g., private practice, hospital employed, government/military, and hybrid employment groups) versus university located practice settings (e.g., work is primarily conducted in a neonatal intensive care unit (NICU) setting located within a university organization). Median quantile regression was used to conduct univariate and multivariate analyses using SAS Software version 9.4. RESULTS: We received 348 responses (26.7% response rate). Median salary was $220,000 (interquartile range: $200,000-250,000). Factors associated with salary include academic rank (instructor: $196,000; assistant professor: $220,000 [12% increase; p < 0.001]; associate professor: $260,000 [18% increase]; p = 0.027) and years of experience (p = 0.017), after adjusting for relevant factors. Employment location, practice type, group size, clinical schedule, location of medical school training, and gender identity did not significantly influence salary in multivariate quantile regression. Median annual bonus was $7,000 higher for nonuniversity located positions ($20,000 vs. 13,000; p = 0.021), with assumption of additional administrative roles and practice group seniority as most commonly cited bonus criteria (p = 0.002 and <0.001, respectively). CONCLUSION: Academic rank and years of experience may influence salary. Bonus earnings are higher for nonuniversity located positions. Employment models are evolving to incorporate academic teaching appointments while practicing in nonuniversity located NICUs. This is the first detailed compensation analysis of early career neonatologists. KEY POINTS: · Transparent compensation data specific to early career neonatologists is lacking.. · Associated factors influential to compensation of early career neonatologists remain unclear.. · This study identifies years of experience and academic rank as possible factors influencing salary earnings of early career neonatologists.. · Practicing in nonuniversity located positions was associated with greater bonus earning potential..

Workforce Characterisustics of Early Career Neonatologists and Comparison of Practice Sites.

OBJECTIVE: Transitioning into the early career physician workforce is a uniquely challenging period in a neonatologist's career. There are limited educational opportunities in fellowship regarding career progression, practice models, and benefits. Understanding these factors are key when searching for employment. This study evaluates the early career neonatologist (ECN) workforce and employment characteristics to improve identification of professional needs. STUDY DESIGN: An anonymous 59-question cross-sectional survey was distributed in July 2020 to members of the American Academy of Pediatrics Section on Neonatal Perinatal Medicine Trainees and Early Career Neonatologists (TECaN). The survey instrument was designed using SurveyMonkey and assessed search methods for identifying employers, employment contract details, and professional duties. Questions addressed clinical service time, level of acuity, protected research time, financial compensation, benefits, job search methods, and promotion requirements. Comparisons were drawn between respondents exclusively working in a university-based setting and respondents employed in nonuniversity locations. Responses were collected using SurveyMonkey and then extracted to a Microsoft Excel Workbook for analysis. Statistical analysis was performed using SAS version 9.4. RESULTS: Of 1,302 eligible members, 348 people responded (26.7%). Forty-six percent of respondents worked in a university setting and 54% worked in a nonuniversity setting. Using employment site as a discriminator, significant differences were noted in scheduling models. University-located respondents were more likely to work 2-week block schedules, fewer weekend/weeknight call, less clinical weeks per year, and more research/administrative weeks per year. Between university and nonuniversity located positions, benefits were largely comparable, while factors perceived as influential toward promotion varied depending on practice site. CONCLUSION: This study provides ECNs with a contemporary workforce description vital to graduating TECaN seeking employment or renegotiating professional obligations. While benefits were largely similar based on practice site, promotion factors and scheduling models may vary depending on location. KEY POINTS: · Data specific to informing employment decisions for graduating Trainees and Early Career Neonatologists are limited.. · This study provides benchmarks for evaluating employment opportunities presented to early career neonatologists.. · Practice site can influence promotion factors..

Do you need a roadmap or can someone give you directions: When school-focused possible identities change so do academic trajectories.

INTRODUCTION: Despite the assumed importance of school-focused possible identities for academic motivation and outcomes, interventions rarely assess the effect of intervention on possible identities. This may be due to difficulty coding open-ended text at scale but leaves open a number of questions: 1) how do school-focused possible identities change over the course of the school year, 2) whether these changes are associated with changes in school outcomes, and 3) whether a machine coding approach is viable. METHODS: In Study 1 (n = 247 Chicago 8th-graders) we assess fall-to-spring change in school-focused possible identities. We test whether change in school-focused possible identities predicts 8th-grade academic outcomes. We include robustness checks. Then we examine school context effects. In Study 2 (n = 1006 Chicago 8th-graders) we address the problem of coding at scale, using a separate data set to train a machine-learning algorithm. RESULTS: On average, school-focused possible identities decline over the school year. But nearly a third of students have increasing school-focused possible identity scores. Increase is associated with improved grades. School context influences whether linked strategies matter. Our machine-learning algorithm accurately classifies school-focused possible identities in our original sample and this school-focused classification reliably predicts academic trajectories. CONCLUSIONS: Change in school-focused possible identities is normative over the course of the school year, interventions should take this into account. On average, students have fewer school-focused possible identities by spring. This decline is associated with declining academic trajectories. However, when school-focused possible identities increase, so do grades. Whether strategies matter is context dependent.

Engraftment of a galactose receptor footprint onto adeno-associated viral capsids improves transduction efficiency.

New viral strains can be evolved to recognize different host glycans through mutagenesis and experimental adaptation. However, such mutants generally harbor amino acid changes that affect viral binding to a single class of carbohydrate receptors. We describe the rational design and synthesis of novel, chimeric adeno-associated virus (AAV) strains that exploit an orthogonal glycan receptor for transduction. A dual glycan-binding AAV strain was first engineered as proof of concept by grafting a galactose (Gal)-binding footprint from AAV serotype 9 onto the heparan sulfate-binding AAV serotype 2. The resulting chimera, AAV2G9, continues to bind heparin affinity columns but interchangeably exploits Gal and heparan sulfate receptors for infection, as evidenced by competitive inhibition assays with lectins, glycans, and parental AAV strains. Although remaining hepatotropic like AAV2, the AAV2G9 chimera mediates rapid onset and higher transgene expression in mice. Similarly, engraftment of the Gal footprint onto the laboratory-derived strain AAV2i8 yielded an enhanced AAV2i8G9 chimera. This new strain remains liver-detargeted like AAV2i8 while selectively transducing muscle tissues at high efficiency, comparable with AAV9. The AAV2i8G9 chimera is a promising vector candidate for targeted gene therapy of cardiac and musculoskeletal diseases. In addition to demonstrating the modularity of glycan receptor footprints on viral capsids, our approach provides design strategies to expand the AAV vector toolkit.

Biophysical and ultrastructural characterization of adeno-associated virus capsid uncoating and genome release.

We describe biophysical and ultrastructural differences in genome release from adeno-associated virus (AAV) capsids packaging wild-type DNA, recombinant single-stranded DNA (ssDNA), or dimeric, self-complementary DNA (scDNA) genomes. Atomic force microscopy and electron microscopy (EM) revealed that AAV particles release packaged genomes and undergo marked changes in capsid morphology upon heating in physiological buffer (pH 7.2). When different AAV capsids packaging ss/scDNA varying in length from 72 to 123% of wild-type DNA (3.4 to 5.8 kb) were incrementally heated, the proportion of uncoated AAV capsids decreased with genome length as observed by EM. Genome release was further characterized by a fluorimetric assay, which demonstrated that acidic pH and high osmotic pressure suppress genome release from AAV particles. In addition, fluorimetric analysis corroborated an inverse correlation between packaged genome length and the temperature needed to induce uncoating. Surprisingly, scAAV vectors required significantly higher temperatures to uncoat than their ssDNA-packaging counterparts. However, externalization of VP1 N termini appears to be unaffected by packaged genome length or self-complementarity. Further analysis by tungsten-shadowing EM revealed striking differences in the morphologies of ssDNA and scDNA genomes upon release from intact capsids. Computational modeling and molecular dynamics simulations suggest that the unusual thermal stability of scAAV vectors might arise from partial base pairing and optimal organization of packaged scDNA. Our work further defines the biophysical mechanisms underlying adeno-associated virus uncoating and genome release.

Common questions about outpatient care of premature infants.

Preterm births (deliveries before 37 weeks' gestation) comprise 12% of all U.S. births and are responsible for onethird of all infant deaths. Neonatal medical advances have increased survival, and primary care physicians often care for infants who were in the neonatal intensive care unit after birth. Functions of the primary care physician include coordination of medical and social services, nutritional surveillance, and managing conditions associated with prematurity. Parental guidance and encouragement are often necessary to ensure appropriate feeding and infant weight gain. Enriched formula and nutrient fortifiers are used for infants with extrauterine growth restriction. Iron supplementation is recommended for breastfed infants, and iron-fortified formula for formula-fed infants. Screening for iron deficiency anemia in preterm infants should occur at four months of age and at nine to 12 months of age. Gastroesophageal reflux is best treated with nonpharmacologic options because medications provide no long-term benefits. Neurodevelopmental delay occurs in up to 50% of preterm infants. Developmental screening should be performed at every well-child visit. If developmental delay is suspected, more formalized testing may be required with appropriate referral. To prevent complications from respiratory syncytial virus infection, palivizumab is recommended in the first year of life during the respiratory syncytial virus season for all infants born before 29 weeks' gestation and for infants born between 29 and 32 weeks' gestation who have chronic lung disease. Most preterm infants have minimal longterm sequelae.

Child Health and the Neonatal-Perinatal Medicine Workforce: 2020-2040.

In 2022, 3.7 million children were born in the United States, of whom ∼600 000 received care from a neonatologist. The dramatic growth of the neonatal-perinatal medicine (NPM) workforce from 375 in 1975 to 5250 in 2022 has paralleled exploding clinical demand. As newborn medicine continues to push the limits of gestational viability and medical complexity, the NPM workforce must advance in numbers, clinical capability, scientific discovery, and leadership. This article, as part of an American Board of Pediatrics Foundation-sponsored supplement that is designed to project the future of the pediatric subspecialty workforce, features a discussion of the NPM workforce's history and current status, factors that have shaped its current profile, and some plausible scenarios of the workforce's needs and configuration in the future. In the article, we use an analytical model that forecasts the growth trajectory of the neonatologist workforce from 2020 through 2040. The model uses recent data on the number of neonatologists and clinical work equivalents per 100 000 children and projects future workforce supply under several theoretical scenarios created by modifying key baseline parameters. The predictions of this model confirm the need for a greater sustainable clinical capacity of the NPM workforce. Several future trends indicate that there may be geographic shortages of neonatologists, similar to expected shortages in other pediatric subspecialties. We do not address what an appropriate target for workforce size should be with the model or this article because the current and projected geographic variability in the NPM workforce and risk-appropriate care suggest that a uniform answer is unlikely.

Intercalation as a means to suppress cyclization and promote polymerization of base-pairing oligonucleotides in a prebiotic world.

The RNA world hypothesis proposes that nucleic acids were once responsible for both information storage and chemical catalysis, before the advent of coded protein synthesis. However, it is difficult to imagine how nucleic acid polymers first appeared, as the abiotic chemical formation of long nucleic acid polymers from mononucleotides or short oligonucleotides remains elusive, and barriers to achieving this goal are substantial. One specific obstacle to abiotic nucleic acid polymerization is strand cyclization. Chemically activated short oligonucleotides cyclize efficiently, which severely impairs polymer growth. We show that intercalation, which stabilizes and rigidifies nucleic acid duplexes, almost totally eliminates strand cyclization, allowing for chemical ligation of tetranucleotides into duplex polymers of up to 100 base pairs in length. In contrast, when these reactions are performed in the absence of intercalators, almost exclusively cyclic tetra- and octanucleotides are produced. Intercalator-free polymerization is not observed, even at tetranucleotide concentrations > 10,000-fold greater than those at which intercalators enable polymerization. We also demonstrate that intercalation-mediated polymerization is most favored if the size of the intercalator matches that of the base pair; intercalators that bind to Watson-Crick base pairs promote the polymerization of oligonucleotides that form these base pairs. Additionally, we demonstrate that intercalation-mediated polymerization is possible with an alternative, non-Watson-Crick-paired duplex that selectively binds a complementary intercalator. These results support the hypothesis that intercalators (acting as 'molecular midwives') could have facilitated the polymerization of the first nucleic acids and possibly helped select the first base pairs, even if only trace amounts of suitable oligomers were available.

Pediatric Primary Health Care: The Central Role of Pediatricians in Maintaining Children's Health in Evolving Health Care Models.

Pediatric primary health care (PPHC) is of principal importance to the health and development of all children, helping them reach their true potential. Pediatricians, as the clinicians most intensively trained and experienced in child health, are the natural leaders of PPHC within the context of the medical home. Given the rapidly evolving models of pediatric health care delivery, including the explosion of telehealth in the wake of the COVID-19 pandemic, pediatricians, together with their representative national organizations such as the American Academy of Pediatrics (AAP), are the most capable clinicians to guide policy innovations on both the local and national stage.

Glycated AAV vectors: chemical redirection of viral tissue tropism.

A chemical approach for selective masking of arginine residues on viral capsids featuring an exogenous glycation reaction has been developed. Reaction of adeno-associated viral (AAV) capsids with the α-dicarbonyl compound, methylglyoxal, resulted in formation of arginine adducts. Specifically, surface-exposed guanidinium side chains were modified into charge neutral hydroimidazolones, thereby disrupting a continuous cluster of basic amino acid residues implicated in heparan sulfate binding. Consequent loss in heparin binding ability and decrease in infectivity were observed. Strikingly, glycated AAV retained the ability to infect neurons in the mouse brain and were redirected from liver to skeletal and cardiac muscle following systemic administration in mice. Further, glycated AAV displayed altered antigenicity demonstrating the potential for evading antibody neutralization. Generation of unnatural amino acid side chains through capsid glycation might serve as an orthogonal strategy to engineer AAV vectors displaying novel tissue tropisms for gene therapy applications.

Seeking racial and ethnic equity among neonatologists.

OBJECTIVE: Racial and ethnic inequities in leadership achievement, compensation, scholarly productivity, and grant funding exists among physicians. This study explores whether similar inequities exist among neonatologists within the United States. STUDY DESIGN: A voluntary anonymous survey was distributed to members of the American Academy of Pediatrics Section on Neonatal-Perinatal Medicine with 560 respondents. Logistic regression and ordinary least squares were used to assess whether racial and ethnic identity is associated with clinical time, leadership, compensation, publication, grant funding, or academic rank. RESULTS: As compared to non-Hispanic White neonatologists, statistical differences were found for underrepresented minorities in medicine in: regions of the country where they worked, total cash compensation received, being awarded an NIH grant, and location of graduate medical education. Fewer differences were found for Asian neonatologists and included location of graduate medicine education. CONCLUSION: Racial and ethnic identity remains a significant independent factor influencing professional achievement and compensation.

Equity for women in medicine-neonatologists identify issues.

OBJECTIVE: Inequity between genders with regards to leadership achievement, compensation, scholarly productivity, and grant funding exist among physicians. This study explores whether similar inequities exist among board certified neonatologists within the USA. STUDY DESIGN: A voluntary anonymous survey was distributed to 3575 members of the American Academy of Pediatrics Section on Neonatal-Perinatal Medicine with 560 respondents (15.7% response rate). The survey contained questions assessing clinician characteristics, work environment, compensation, professional productivity, and social factors. Statistical analysis was done using JMP Pro 15.0.0 by SAS. RESULTS: Female neonatologists, compared to male peers, were less likely to hold leadership positions (OR 0.36, p = 0.005), received lower compensation by an average of $34,916 or 12.47% (p < 0.001), and had 6.71 fewer primary authored publications (p = 0.025) after adjusting for several confounding factors. CONCLUSION: Gender remains a significant independent factor influencing leadership attainment, compensation, and academic productivity in this cohort of neonatologists.

Solution structure and thermodynamics of 2',5' RNA intercalation.

As a means to explore the influence of the nucleic acid backbone on the intercalative binding of ligands to DNA and RNA, we have determined the solution structure of a proflavine-bound 2',5'-linked octamer duplex with the sequence GCCGCGGC. This structure represents the first NMR structure of an intercalated RNA duplex, of either backbone structural isomer. By comparison with X-ray crystal structures, we have identified similarities and differences between intercalated 3',5' and 2',5'-linked RNA duplexes. First, the two forms of RNA have different sugar pucker geometries at the intercalated nucleotide steps, yet have the same interphosphate distances. Second, as in intercalated 3',5' RNA, the phosphate backbone angle zeta at the 2',5' RNA intercalation site prefers to be in the trans conformation, whereas unintercalated 2',5' and 3',5' RNA prefer the -gauche conformation. These observations provide new insights regarding the transitions required for intercalation of a phosphodiester-ribose backbone and suggest a possible contribution of the backbone to the origin of the nearest-neighbor exclusion principle. Thermodynamic studies presented for intercalation of both structural RNA isomers also reveal a surprising sensitivity of intercalator binding enthalpy and entropy to the details of RNA backbone structure.

Neonatologist salary: factors, equity and gender.

OBJECTIVE: Physician compensation has been found to be influenced by gender, academic affiliation, specialty, productivity, and time in practice. This study explores their impact in the field of neonatology to inform institutional strategic planning and decisions by current and future practitioners. STUDY DESIGN: A voluntary anonymous survey was distributed to members of the American Academy of Pediatrics Section on Neonatal-Perinatal Medicine with a 15% response rate. The survey contained questions assessing clinician characteristics, work environment, and professional productivity. Statistical analysis was done using JMP Pro 14.0.0 by SAS. RESULTS: Median salary was $256,000 (interquartile range, $213,608-315,000). Generalized linear model found that years post fellowship, academic affiliation, gender, practice location, professional duties, and clinical team member types independently influenced expected salary. CONCLUSION: Several factors influence the expected compensation of this cohort of neonatologists, even after adjustments for differences in clinician characteristics, work environment, and productivity.

The interplay of prolactin and the glucocorticoids in the regulation of beta-cell gene expression, fatty acid oxidation, and glucose-stimulated insulin secretion: implications for carbohydrate metabolism in pregnancy.

Carbohydrate metabolism in pregnancy reflects the balance between counterregulatory hormones, which induce insulin resistance, and lactogenic hormones, which stimulate beta-cell proliferation and insulin production. Here we explored the interactions of prolactin (PRL) and glucocorticoids in the regulation of beta-cell gene expression, fatty acid oxidation, and glucose-stimulated insulin secretion (GSIS). In rat insulinoma cells, rat PRL caused 30-50% (P < 0.001) reductions in Forkhead box O (FoxO)-1, peroxisome proliferator activator receptor (PPAR)-gamma coactivator-1alpha (PGC-1alpha), PPARalpha, and carnitine palmitoyltransferase 1 (CPT-1) mRNAs and increased Glut-2 mRNA and GSIS; conversely, dexamethasone (DEX) up-regulated FoxO1, PGC1alpha, PPARalpha, CPT-1, and uncoupling protein 2 (UCP-2) mRNAs in insulinoma cells and inhibited GSIS. Hydrocortisone had similar effects. The effects of DEX were attenuated by coincubation of cells with PRL. In primary rat islets, PRL reduced FoxO1, PPARalpha, and CPT-1 mRNAs, whereas DEX increased FoxO1, PGC1alpha, and UCP-2 mRNAs. The effects of PRL on gene expression were mimicked by constitutive overexpression of signal transducer and activator of transcription-5b. PRL induced signal transducer and activator of transcription-5 binding to a consensus sequence in the rat FoxO1 promoter, reduced nuclear FoxO1 protein levels, and induced its phosphorylation and cytoplasmic redistribution. DEX increased beta-cell fatty acid oxidation and reduced fatty acid esterification; these effects were attenuated by PRL. Thus, lactogens and glucocorticoids have opposing effects on a number of beta-cell genes including FoxO1, PGC1alpha, PPARalpha, CPT-1, and UCP-2 and differentially regulate beta-cell Glut-2 expression, fatty acid oxidation, and GSIS. These observations suggest new mechanisms by which lactogens may preserve beta-cell mass and function and maternal glucose tolerance despite the doubling of maternal cortisol concentrations in late gestation.

Small molecule-mediated duplex formation of nucleic acids with 'incompatible' backbones.

Proflavine, a known intercalator of DNA and RNA, promotes duplex formation by nucleic acids with natural and non-natural backbones that otherwise form duplexes with low thermal stability, and even some that show no sign of duplex formation in the absence of proflavine. These findings demonstrate the potential for intercalators to be used as cofactors for the assembly of rationally designed nucleic acid structures, and could provide fundamental insights regarding intercalation of natural nucleic acid duplexes.

Aspirin inhibits surface glycoprotein IIb/IIIa, P-selectin, CD63, and CD107a receptor expression on human platelets.

Platelet inhibition after aspirin therapy reduces the risk for the development of acute coronary syndromes. However, the mechanism by which aspirin affect platelets other than by prostaglandin blockade is unclear. We sought to determine the in vitro effects of aspirin on the surface expression of nine platelet receptors using whole blood flow cytometry. Blood from 24 healthy volunteers was incubated for 30 min with 1.8 and 7.2 mg/l phosphate-buffered saline-diluted acetylsalicylic acid in the presence or absence of apyrase. Platelet serotonin release, and the surface expression of platelet receptors with or without apyrase were determined using the following monoclonal antibodies: anit-CD41 [glycoprotein (GP)IIb/IIIa], CD42b (GPIb), CD62p (P-selectin), CD51/CD61 (vitronectin receptor), CD31 [platelet/endothelial cellular adhesion molecule-1 (PECAM-1)], CD107a [lysosomal associated membrane protein (LAMP)-1], CD107b (LAMP-2), CD63 (LIMP or LAMP-3), and CD151 (PETA-3). Samples were then immediately fixed with 2% paraformaldehyde, and run on the flow cytometer within 48 h. Aspirin does not affect serotonin release from human platelets. Dose-dependent inhibition of GPIIb/IIIa, P-selectin, CD63, and CD107a receptor expression was observed in the aspirin-treated whole-blood samples. Apyrase potentiates the effects of aspirin, and independently inhibits PECAM-1. In addition to the known effect of irreversibly inhibiting platelet cyclooxygenase-1, thereby blocking thromboxane A(2) synthesis, it appears that aspirin exhibits direct effects on selective major platelet receptors.

Effects of in vitro exposure of alcohol on surface receptor expression of human platelets.

Platelet inhibition after moderate alcohol consumption in patients with ischaemic heart disease may contribute to reducing the risk for developing acute coronary syndromes. However, the mechanism by which ethanol affects platelets is not clarified. We sought to determine the in vitro effects of alcohol on the surface expression of human platelet receptors using whole blood flow cytometry. Blood samples from 10 healthy volunteers were incubated for 30 min with 25 and 50 mmol l(-1) of phosphate buffered saline diluted grain ethanol, concentrations often used in in vitro studies. The surface expression of platelet receptors was determined by flow cytometry after fixation with 2% paraformaldehyde using the following monoclonal antibodies: CD 41 (GP IIb/IIIa), CD 42b (GP Ib), CD 62p (P-selectin), CD 51/CD 61 (vitronectin receptor), CD 31 (PECAM-1), CD 107a (LAMP-1), CD 107b (LAMP-2), CD 63 (LIMP, LAMP-3) and CD 151 (PETA-3). Dose-dependent inhibition of GP IIb/IIIa, P-selectin, CD 63 and CD 107a receptor expression was observed in the ethanol-treated whole blood samples. This study for the first time establishes a direct effect of ethanol on selective major platelet receptors. Beneficial cardiovascular properties of moderate alcohol consumption may be explained by ethanol's antiplatelet action.

Tyrosine cross-linking reveals interfacial dynamics in adeno-associated viral capsids during infection.

Viral capsid dynamics are often observed during infectious events such as cell surface attachment, entry and genome release. Structural analysis of adeno-associated virus (AAV), a helper-dependent parvovirus, revealed a cluster of surface-exposed tyrosine residues at the icosahedral two-fold symmetry axis. We exploited the latter observation to carry out selective oxidation of Tyr residues, which yielded cross-linked viral protein (VP) subunit dimers, effectively "stitching" together the AAV capsid two-fold interface. Characterization of different Tyr-to-Phe mutants confirmed that the formation of cross-linked VP dimers is mediated by dityrosine adducts and requires the Tyr704 residue, which crosses over from one neighboring VP subunit to the other. When compared to unmodified capsids, Tyr-cross-linked AAV displayed decreased transduction efficiency in cell culture. Surprisingly, further biochemical and quantitative microscopy studies revealed that restraining the two-fold interface hinders externalization of buried VP N-termini, which contain a phospholipase A2 domain and nuclear localization sequences critical for infection. These adverse effects caused by tyrosine oxidation support the notion that interfacial dynamics at the AAV capsid two-fold symmetry axis play a role in externalization of VP N-termini during infection.