Pharmacovigilance study of BCR-ABL1 tyrosine kinase inhibitors: a safety analysis of the FDA adverse event reporting system.

BACKGROUND: With the increased use of BCR-ABL1 tyrosine kinase inhibitors (TKIs) in cancer patients, adverse events (AEs) have garnered considerable interest. We conducted this pharmacovigilance study to evaluate the AEs of BCR-ABL1 TKIs in cancer patients using the Food and Drug Administration Adverse Event Reporting System (FAERS) database. METHODS: To query AE reports from the FAERS database, we used OpenVigil 2.1. Descriptive analysis was then employed to describe the characteristics of TKIs-associated AE reports. We also utilized the disproportionality analysis to detect safety signals by calculating the proportional reporting ratio (PRR) and reporting odds ratios (ROR). RESULTS: From the FAERS database, a total of 85,989 AE reports were retrieved, with 3,080 significant AE signals identified. Specifically, imatinib, nilotinib, dasatinib, bosutinib, and ponatinib had significant AE signals of 1,058, 813, 232, 186, and 791, respectively. These significant signals were further categorized into 26 system organ classes (SOCs). The AE signals of imatinib and ponatinib were primarily associated with general disorders and administration site conditions. On the other hand, nilotinib, dasatinib, and bosutinib were mainly linked to investigations, respiratory, thoracic and mediastinal disorders, and gastrointestinal disorders, respectively. Notably, new signals of 245, 278, 47, 55, and 253 were observed in imatinib, nilotinib, dasatinib, bosutinib, and ponatinib, respectively. CONCLUSIONS: The results of this study demonstrated that AE signals differ among the five BCR-ABL1 TKIs. Furthermore, each BCR-ABL1 TKI displayed several new signals. These findings provide valuable information for clinicians aiming to reduce the risk of AEs during BCR-ABL1 TKI treatment.

Pharmacovigilance Study of Infigratinib: A Safety Analysis of the FDA Adverse Event Reporting System.

BACKGROUND: Infigratinib is a fibroblast growth factor receptor (FGFR)-specifc tyrosine kinase inhibitor indicated for the treatment of patients with previously treated, unresectable, locally advanced or metastatic cholangiocarcinoma. However, few studies have been conducted to evaluated the safety of infigratinib in the real world. In this study, we conducted a pharmacovigilance study to evaluate the adverse events (AEs) of infigratinib by using the Food and Drug Administration Adverse Event Reporting System (FAERS) database. METHODS: OpenVigil 2.1 was employed to extract the FAERS database. Descriptive analysis was used to describe the characteristics of infigratinib-associated AE reports. Disproportionality analysis was performed by calculating the proportional reporting ratio (PRR), reporting odds ratios (ROR), and Bayesian analysis confidence propagation neural network (BCPNN) to detect positive signals. RESULTS: Our findings revealed 149 AE reports, among which 36 significant signals were identified. These significant AE signals were mainly observed in gastrointestinal disorders (N = 26, ROR = 26.03, PRR = 8.44, information component [IC] = 3.08) and skin and subcutaneous tissue disorders (N = 21, ROR = 92.13, PRR = 40.41, IC = 5.34). Notably, dehydration and skin exfoliation were unexpected AEs, but had relatively high signal intensities (ROR = 29.75, PRR = 26.64, IC = 4.74; ROR = 50.61, PRR = 45.24, IC = 5.50, respectively) despite not being listed on the drug label. Furthermore, our analysis showed that infigratinib dose differed statistically between severe and non-severe reports (113.82 ± 16.13 mg vs 125 ± 0.00 mg, t = - 4.28; p < 0.001). However, there were no significant differences in sex, age, and types of AEs between the two groups (p  = 0.06, p  = 0.86, and p = 0.93, respectively). CONCLUSIONS: These findings suggest that gastrointestinal and skin toxicities are the most common adverse reactions for infigratinib. It is important to recognize skin exfoliation and dehydration in clinical practice, as they are unexpected AEs. Additionally, our study indicates that infigratinib dose may correlate with an increased risk of AE severity, highlighting the need for dose adjustment of infigratinib when exposure to the drug is increased due to internal or external factors.

Cas9-mediated knockout of Ndrg2 enhances the regenerative potential of dendritic cells for wound healing.

Chronic wounds impose a significant healthcare burden to a broad patient population. Cell-based therapies, while having shown benefits for the treatment of chronic wounds, have not yet achieved widespread adoption into clinical practice. We developed a CRISPR/Cas9 approach to precisely edit murine dendritic cells to enhance their therapeutic potential for healing chronic wounds. Using single-cell RNA sequencing of tolerogenic dendritic cells, we identified N-myc downregulated gene 2 (Ndrg2), which marks a specific population of dendritic cell progenitors, as a promising target for CRISPR knockout. Ndrg2-knockout alters the transcriptomic profile of dendritic cells and preserves an immature cell state with a strong pro-angiogenic and regenerative capacity. We then incorporated our CRISPR-based cell engineering within a therapeutic hydrogel for in vivo cell delivery and developed an effective translational approach for dendritic cell-based immunotherapy that accelerated healing of full-thickness wounds in both non-diabetic and diabetic mouse models. These findings could open the door to future clinical trials using safe gene editing in dendritic cells for treating various types of chronic wounds.

Transporter­mediated drug­drug interactions involving poly (ADP­ribose) polymerase inhibitors (Review).

Poly (ADP ribose) polymerase (PARP) inhibitors are novel targeted anticancer agents that have been widely used in patients with cancer, particularly in patients with breast-related cancer antigen 1/2 mutations. PARP inhibitors are administered orally and have been associated with improved efficacy and toxicity profiles when compared to conventional chemotherapy agents; this improvement is convenient and results in good compliance among patients with cancer. However, as PARP inhibitors are administered long-term and frequently concomitantly with other therapeutic agents, the risk of drug-drug interactions (DDIs) is increasing. Transporters are widely expressed in numerous types of tissue, where they have crucial roles in the membrane transport of several drugs. An alteration in the activity and expression of transporters may change the drug pharmacokinetics (PKs) and cause DDIs. As the five PARP inhibitors (olaparib, niraparib, rucaparib, talazoparib and veliparib) are transporter substrates, inhibitors or inducers, the potential transporter-mediated DDIs with the use of PARP inhibitors should be taken into consideration when co-administered with other agents. The present review focused on recent findings on transporter-mediated DDIs with PARP inhibitors to provide specific recommendations for reducing the occurrence of undesired DDIs.

Effects of hepatic or renal impairment on the pharmacokinetics of immune checkpoint inhibitors.

Immune checkpoint inhibitors (ICIs) have become the cornerstone in treating many solid and hematological cancers. The ICIs, including anti-cytotoxic T lymphocyte-associated protein 4 (CTLA-4), anti-programed cell death 1 (PD-1), and anti-programed death-ligand 1 (PD-L1) monoclonal antibodies, have significantly improved the prognosis of cancer patients. Meanwhile, the incidence of hepatic or renal impairment in cancer patients is increasing. However, data about the efficacy and safety of ICIs in patients with hepatic or renal impairment are limited. In this review, we characterize and summarize the pharmacokinetics (PK) of ICIs as well as the effects of hepatic or renal function on the PK of ICIs, and provide specific recommendations for clinicians when prescribing ICIs in patients with hepatic or renal impairment.

Dose Adjustment of Poly (ADP­Ribose) Polymerase Inhibitors in Patients with Hepatic or Renal Impairment.

Poly (ADP-ribose) polymerase (PARP) inhibitors are small-molecule inhibitors of PARP enzymes (including PARP1, PARP2, and PARP3) that exhibit activity against tumor cells with defects in DNA repair. In recent years, five PARP inhibitors, olaparib, niraparib, rucaparib, talazoparib and veliparib, have been developed for the treatment of solid tumors, particularly in patients with breast-related cancer antigen (BRCA) 1/2 mutations, or those without a functional homologous recombination repair pathway. These novel treatments exhibit improved efficacy and toxicity when compared to conventional chemotherapy agents. The five PARP inhibitors are eliminated primarily via the liver and kidneys, hepatic or renal impairment may significantly affect their pharmacokinetics (PK). Therefore, it is important to know the effects of hepatic or renal impairment on the PK and safety of PARP inhibitors. In this review, we characterize and summarize the effects of hepatic and renal function on the PK of PARP inhibitors and provide specific recommendations for clinicians when prescribing PARP inhibitors in patients with hepatic or renal impairment.

Genomic analysis of 9 infants with hypermethioninemia by whole-exome sequencing among in Henan, China.

BACKGROUND: Hypermethioninemia is an inborn error of metabolism with elevated plasma methionine (Met) caused by methionine adenosyltransferase deficiency. Methionine adenosyltransferase (MAT) I/III deficiency is the most common cause of hypermethioninemia. Except for increased blood Met, most patients have no symptoms, but a small number have nervous system complications, including cognitive impairment and mental retardation. OBJECTIVE: To investigate the gene variation of patients with hypermethioninemia in newborns in Henan province. METHODS: 9 cases of hypermethioninemia were screened for amino acids profile and acyl carnitine by tandem mass spectrometric (MS/MS) among 245 054 newborns. We performed whole-exome sequencing on 9 families of infants with hypermethioninemia. We identified mutated genes under different models of inheritance and further assessed these mutations through Sanger sequencing and association analysis. RESULTS: The incidence of neonatal hypermethioninemia was 1:27 228 in Henan province. A total of ten mutations in the MAT1A gene in the 9 patients were identified, including nine reported mutations (c.1070C > T, c.895C > T, c.100 T > A, c.315C > A, c.529C > T, c.623A > C, c.407G > T, c.1066C > T, 867G > T) and one novel mutations (c.772G > C). c.772G > C was detected in 2 families and is the most common variant. 7 infants (7/9) with hypermethioninemia were genetically autosomal dominant, and 2 infants (2/9) with hypermethioninemia were genetically autosomal recessive. CONCLUSION: Our findings expand the mutational spectrum of hypermethioninemia, with the description of one new mutation. They improve the understanding of the genetic background and clinical manifestation of MAT1A in Chinese patients.

Dual CRISPR interference and activation for targeted reactivation of X-linked endogenous FOXP3 in human breast cancer cells.

BACKGROUND: Unlike autosomal tumor suppressors, X-linked tumor suppressors can be inactivated by a single hit due to X-chromosome inactivation (XCI). Here, we argue that targeted reactivation of the non-mutated allele from XCI offers a potential therapy for female breast cancers. METHODS: Towards this goal, we developed a dual CRISPR interference and activation (CRISPRi/a) approach for simultaneously silencing and reactivating multiple X-linked genes using two orthogonal, nuclease-deficient CRISPR/Cas9 (dCas9) proteins. RESULTS: Using Streptococcus pyogenes dCas9-KRAB for silencing XIST and Staphylococcus aureus dCas9-VPR for activating FOXP3, we achieved CRISPR activation of FOXP3 in various cell lines of human female breast cancers. In human breast cancer HCC202 cells, which express a synonymous heterozygous mutation in the coding region of FOXP3, simultaneous silencing of XIST from XCI led to enhanced and prolonged FOXP3 activation. Also, reactivation of endogenous FOXP3 in breast cancer cells by CRISPRi/a inhibited tumor growth in vitro and in vivo. We further optimized CRISPRa by fusing dCas9 to the demethylase TET1 and observed enhanced FOXP3 activation. Analysis of the conserved CpG-rich region of FOXP3 intron 1 confirmed that CRISPRi/a-mediated simultaneous FOXP3 activation and XIST silencing were accompanied by elevated H4 acetylation, including H4K5ac, H4K8ac, and H4K16ac, and H3K4me3 and lower DNA methylation. This indicates that CRISPRi/a targeting to XIST and FOXP3 loci alters their transcription and their nearby epigenetic modifications. CONCLUSIONS: The simultaneous activation and repression of the X-linked, endogenous FOXP3 and XIST from XCI offers a useful research tool and a potential therapeutic for female breast cancers.

Metabolism­related pharmacokinetic drug­drug interactions with poly (ADP­ribose) polymerase inhibitors (Review).

Poly (ADP­ribose) polymerase (PARP) inhibitors, including olaparib, niraparib, rucaparib, talazoparib and veliparib, have emerged as one of the most exciting new treatments for solid tumors, particularly in patients with breast­related cancer antigen 1/2 mutations. Oral administration is convenient and shows favorable compliance with the majority of patients, but it may be affected by numerous factors, including food, metabolic enzymes and transporters. These interactions may be associated with serious adverse drug reactions or may reduce the treatment efficacy of PARP inhibitors. In fact, numerous pharmacokinetic (PK)­based drug­drug interactions (DDIs) involve the metabolism of PARP inhibitors, particularly those metabolized via cytochrome P450 enzymes. The present review aims to characterize and summarize the metabolism­related PK­based DDIs of PARP inhibitors, and to provide specific recommendations for reducing the risk of clinically significant DDIs.

Aidi injection combined with chemotherapy in the treatment of cancer patients: a systematic review of systematic reviews and meta-analyses.

The objective of the study was to evaluate and summarize the evidence from systematic reviews and meta-analyses regarding the efficacy and safety of Aidi injection combined with chemotherapy in the treatment of cancer patients. PubMed, EMBASE, Web of Science, Cochrane Library, China National Knowledge Infrastructure, Chong qing VIP databases, and Wanfang databases were searched for systematic reviews/meta-analyses on the topic of Aidi treating cancer patients published from inception to 20 December 2020. Google Scholar and OpenGrey were searched for grey literature and International Prospective Register of Systematic Reviews for ongoing reviews. Two investigators independently selected eligible studies, extracted data, and assessed the methodological quality of included systematic reviews/meta-analyses using the measurement tool to assess systematic reviews 2 (AMSTAR-2) tool, and the strength of evidence was assessed with the grade of recommendation, assessment, development, and evaluation (GRADE) system. Twenty-seven systematic reviews/meta-analyses were identified in the study. The methodological quality of all 27 systematic reviews/meta-analyses were critically low when evaluated by AMSTAR-2, and the evidence quality of all outcomes rated as either low or very low based on the GRADE system. The available evidence is currently insufficient to support or refute the use of Aidi in the treatment of cancer patients, thus high-quality trials with large sample sizes are needed to explore its efficacy and safety in cancer patients.

Dual Oxidase System Genes Defects in Children With Congenital Hypothyroidism.

PURPOSE: The objectives of this study were to analyze the distribution of dual oxidase (DUOX) system genes (containing DUOX2, DUOX1, DUOXA2, and DUOXA1) variants in children with congenital hypothyroidism (CH) and their phenotypes. METHODS: Target region sequencing technology was performed on DUOX system genes among 606 CH subjects covering all the exon and intron regions. Detailed clinical data were collected for statistical analysis. RESULTS: A total of 95 suspected pathogenic variants were detected in the DUOX system genes, showing a 39.11% rate in variant carrying (237/606). DUOX2 had the highest rate in this study. There were statistical differences in maximum adjusted dose and current dose of levothyroxine between the DUOX system genes nonmutated group with the mutated group (both Ps < 0.001). The cases in the DUOX system genes mutated group were more likely to develop into transient CH (χ 2 = 23.155, P < 0.001) and more likely to manifested as goiter or gland-in-situ (χ 2 = 66.139, P < 0.001). In addition, there was no significant difference in clinical characteristics between DUOX system genes monoallelic and non-monoallelic. Although 20% of the variants affected the functional domain regions (EF hand, flavin adenine dinucleotide and nicotinamide adenine dinucleotide binding sites), there was no significant effect on the phenotype severity whether the variation is located in the functional domain regions. CONCLUSIONS: Our results showed the high variation rate of DUOX2 in the DUOX system genes among Chinese CH patients. The complex genotype-phenotype relationship of DUOX system genes broadened the understanding of CH phenotype spectrum.

Dose adjustment for tyrosine kinase inhibitors in non­small cell lung cancer patients with hepatic or renal function impairment (Review).

In recent years, a number of tyrosine kinase inhibitors (TKIs) have been approved for the treatment of non­small cell lung cancer. These novel treatments exhibit improved efficacy and toxicity when compared to conventional chemotherapy agents. TKIs are administered orally, which has the advantages of improved flexibility and convenience for the patients. However, challenges have arisen in the use of these novel agents. Prescribing drugs for patients with hepatic or renal function impairment poses a challenge for clinicians due to the large pharmacokinetic variability in each individual patient. Moreover, several TKIs have been shown to cause laboratory test abnormalities normally associated with hepatic or renal injury. The aim of the present review was to discuss the effects of hepatic and renal function impairment on the pharmacokinetic variability of 17 TKIs and their potential hepatotoxicity and nephrotoxicity, and to recommend dose adjustment for patients with hepatic or renal impairment.

A New Triangular Rotation and Advancement Pulp Flap for Lateral Oblique Fingertip Defect.

The fingertip is one of the most common sites of traumatic injuries faced by hand surgeons. In cases of lateral oblique amputation, only limited alternatives are available for reconstruction. This study introduced a new method involving rotation and use of an advancement pulp flap for covering lateral oblique defect and evaluated its outcome. METHOD: A series of 12 patients with 14 lateral oblique fingertip defects were recruited in this study. All fingertips were unreplantable and were injured distal to the proximal one-third of nail bed, with phalanx exposed. All cases received surgical reconstruction using a triangular rotation and advancement pulp flap. Static 2-point discrimination, cold intolerance, pain, hypersensitivity, range of motion, and aesthetic satisfaction were evaluated 6 months to 12 months postoperation. RESULT: Bone defect was noted in 7 cases. The area of defect was 10×7-20×12 mm2, and the angle of defect was 30-60 degrees. Mean follow-up was 14.3 months. No hook nail deformity, cold intolerance, and hypersensitivity were observed. One patient complained about pain postoperation, demanding a second operation. Static 2-point discrimination was between 5 and 8 mm in all cases. Range of motion of distal interphalangeal joint recovered to 20-45 degrees at the last follow-up. No stiffness was observed in the interphalangeal or metacarpophalangeal joints. All patients were satisfied with the appearance of the flap. CONCLUSION: The triangular rotation and advancement pulp flap is simple, safe, and reliable for treating lateral oblique defect of fingertip, providing scope for anatomical reconstruction and fair sensation and aesthetic recovery.

Pharmacokinetic-Based Drug-Drug Interactions with Anaplastic Lymphoma Kinase Inhibitors: A Review.

Anaplastic lymphoma kinase (ALK) inhibitors are important treatment options for non-small-cell lung cancer (NSCLC), associated with ALK gene rearrangement. Patients with ALK gene rearrangement show sensitivity to and benefit clinically from treatment with ALK tyrosine kinase inhibitors (ALK-TKIs). To date, crizotinib, ceritinib, alectinib, brigatinib, lorlatinib, and entrectinib have received approval from the US Food and Drug Administration and/or the European Medicines Agency for use during the treatment of ALK-gene-rearrangement forms of NSCLC. Although the oral route of administration is convenient and results in good compliance among patients, oral administration can be affected by many factors, such as food, intragastric pH, cytochrome P450 enzymes, transporters, and p-glycoprotein. These factors can result in increased risks for serious adverse events or can lead to reduced therapeutic effects of ALK-TKIs. This review characterizes and summarizes the pharmacokinetic parameters and drug--drug interactions associated with ALK-TKIs to provide specific recommendations for oncologists and clinical pharmacists when prescribing ALK-TKIs.

Variant analysis of HPD genes from two families showing elevated tyrosine upon newborn screening by tandem mass spectrometry (MS/MS).

Background Alterations in the structure and activity of 4-hydroxyphenylpyruvate dioxygenase (HPD) are causally related to two different metabolic disorders: recessively inherited tyrosinemia type III and dominantly inherited hawkinsinuria. The aim of this study was to provide a new perspective for the clinical understanding of the pathogenesis of tyrosinemia type III or hawkinsinuria. Case presentation A full-term newborn baby born after a safe pregnancy and childbirth with a birth weight of 3200 g and another full-term baby born after a safe pregnancy and childbirth with a birth weight of 2800 g are reported and analysed. DNA extraction, next-generation sequencing, bioinformatics analysis, Sanger sequencing and biochemical analysis were performed. One patient with a heterozygous HPD gene (NM_002150.2) c.460G > A mutation and one patient with a heterozygous HPD gene (NM_002150.2) c.248delG mutation showing elevated tyrosine levels upon newborn screening by tandem mass spectrometry (MS/MS) are reported. Conclusions The HPD gene may not be a strictly autosomal recessive pathogenic gene, which provides a new perspective for the clinical understanding of the pathogenesis of tyrosinemia type III or hawkinsinuria.

CRISPR-mediated live imaging of genome editing and transcription.

We report a robust, versatile approach called CRISPR live-cell fluorescent in situ hybridization (LiveFISH) using fluorescent oligonucleotides for genome tracking in a broad range of cell types, including primary cells. An intrinsic stability switch of CRISPR guide RNAs enables LiveFISH to accurately detect chromosomal disorders such as Patau syndrome in prenatal amniotic fluid cells and track multiple loci in human T lymphocytes. In addition, LiveFISH tracks the real-time movement of DNA double-strand breaks induced by CRISPR-Cas9-mediated editing and consequent chromosome translocations. Finally, by combining Cas9 and Cas13 systems, LiveFISH allows for simultaneous visualization of genomic DNA and RNA transcripts in living cells. The LiveFISH approach enables real-time live imaging of DNA and RNA during genome editing, transcription, and rearrangements in single cells.

Effect of cadmium contamination on the eutrophic secondary pollution of aquatic macrophytes by litter decomposition.

The objective of this study was to identify the effect of cadmium (Cd) contamination on the decomposition of aquatic macrophyte litter and its eutrophic secondary pollution. A laboratory experiment was conducted with three treatments: water Cd contamination (Cd-w), litter Cd contamination (Cd-l) and control (CK). The results showed that CK and Cd-w exhibited the typical decomposition dynamics of litter, i.e., early rapid decomposition followed by slow decomposition, while the litter biomass loss (BL) in Cd-l exhibited an approximately linear relationship with time over the 64-day experimental period. The BL in Cd-l was only 10.8% in the initial 4 days, while that in CK and Cd-w was 59.0% and 54.8%, respectively. Cd inhibited the fluctuation of the water chemical oxygen demand (COD) by reducing both the early increase and the subsequent decrease. The increases in water total nitrogen (TN) and total phosphorus (TP) were inhibited by Cd contamination throughout most of the decomposition period. The alterations of litter quality during the plant growth period and of the bacterial community during the litter decomposition period by Cd contamination could explain the variations in litter decomposition rate and its eutrophic secondary pollution during the early and late decomposition stages, respectively. The Cd inhibition of the eutrophic secondary pollution of aquatic macrophytes has great significance for the improved evaluation of Cd contamination.

Atrial fibrillation following treatment with paclitaxel: A case report.

Paclitaxel (PTX) is an antimicrotubule agent, and is effective in treating a wide range of solid tumors. However, its use may lead to cardiovascular toxicities, the manifestations of which include arrhythmia, heart failure, acute myocardial ischemia and atrial fibrillation (AF). AF is among the severe reactions to the PTX cardiotoxicity, and a cause for substantial morbidity and mortality. However, the incidence of PTX-induced AF is reportedly low (1.0-1.7% worldwide), and few cases have been reported in the literature. Thus, to emphasize the need for awareness of this side effect of PTX among clinicians, the report herein presents a case of AF induced by PTX in a patient with non-small-cell carcinoma. A 51-year-old man experienced AF following treatment with PTX. Amiodarone and metoprolol were administered to the patient to control cardiac rhythm and rate. After 3 days, the electrocardiogram was normalized and indicated normal heart rate and rhythm. According to this case, thorough attention should be paid during PTX treatment to monitor for signs of AF or other abnormalities in cardiac function.

A sterile alpha-motif domain in NafY targets apo-NifDK for iron-molybdenum cofactor delivery via a tethered domain.

NafY participates in the final steps of nitrogenase maturation, having a dual role as iron-molybdenum cofactor (FeMo-co) carrier and as chaperone to the FeMo-co-deficient apo-NifDK (apo-dinitrogenase). NafY contains an N-terminal domain of unknown function (n-NafY) and a C-terminal domain (core-NafY) necessary for FeMo-co binding. We show here that n-NafY and core-NafY have very weak interactions in intact NafY. The NMR structure of n-NafY reveals that it belongs to the sterile α-motif (SAM) family of domains, which are frequently involved in protein-protein interactions. The presence of a SAM domain in NafY was unexpected and could not be inferred from its amino acid sequence. Although SAM domains are very commonly found in eukaryotic proteins, they have rarely been identified in prokaryotes. The n-NafY SAM domain binds apo-NifDK. As opposed to full-length NafY, n-NafY impaired FeMo-co insertion when present in molar excess relative to FeMo-co and apo-NifDK. The implications of these observations are discussed to offer a plausible mechanism of FeMo-co insertion. NafY domain structure, molecular tumbling, and interdomain motion, as well as NafY interaction with apo-NifDK are consistent with the function of NafY in FeMo-co delivery to apo-NifDK.