A Flat BAR Protein Promotes Actin Polymerization at the Base of Clathrin-Coated Pits.

Multiple proteins act co-operatively in mammalian clathrin-mediated endocytosis (CME) to generate endocytic vesicles from the plasma membrane. The principles controlling the activation and organization of the actin cytoskeleton during mammalian CME are, however, not fully understood. Here, we show that the protein FCHSD2 is a major activator of actin polymerization during CME. FCHSD2 deletion leads to decreased ligand uptake caused by slowed pit maturation. FCHSD2 is recruited to endocytic pits by the scaffold protein intersectin via an unusual SH3-SH3 interaction. Here, its flat F-BAR domain binds to the planar region of the plasma membrane surrounding the developing pit forming an annulus. When bound to the membrane, FCHSD2 activates actin polymerization by a mechanism that combines oligomerization and recruitment of N-WASP to PI(4,5)P2, thus promoting pit maturation. Our data therefore describe a molecular mechanism for linking spatiotemporally the plasma membrane to a force-generating actin platform guiding endocytic vesicle maturation.

Polyphyllin I Sensitizes Cisplatin-Resistant Human Cervical Cancer Cells to Cisplatin Treatment.

Cervical cancer (CC) is a common gynecological malignancy, and improving cisplatin sensitivity has become a hot topic in CC chemotherapy research. Polyphyllin I (PPI), a potent bioactive compound found in Rhizoma Paridis, known for its anticancer properties, remains underexplored in CC resistance. In this study, we evaluated PPI's impact on cisplatin-resistant CC cells and elucidated its underlying mechanism. Our findings reveal that PPI enhances the sensitivity of cisplatin-resistant CC cells to the drug, promotes apoptosis, and inhibits cell migration. Mechanistically, PPI was found to regulate p53 expression and its target genes, and suppressing p53 expression reverses PPI's sensitizing effect in drug-resistant CC cells. In conclusion, PPI showed promise in sensitizing cisplatin-resistant human CC cells to cisplatin treatment, suggesting that it could serve as a potent adjunct therapy for cervical cancer, particularly for cases that have developed resistance to cisplatin, thereby providing a promising basis for further clinical investigation into PPI for enhancing the efficacy of existing chemotherapy regimens in resistant cervical cancer.

Structure of KAP1 tripartite motif identifies molecular interfaces required for retroelement silencing.

Transcription of transposable elements is tightly regulated to prevent genome damage. KRAB domain-containing zinc finger proteins (KRAB-ZFPs) and KRAB-associated protein 1 (KAP1/TRIM28) play a key role in regulating retrotransposons. KRAB-ZFPs recognize specific retrotransposon sequences and recruit KAP1, inducing the assembly of an epigenetic silencing complex, with chromatin remodeling activities that repress transcription of the targeted retrotransposon and adjacent genes. Our biophysical and structural data show that the tripartite motif (TRIM) of KAP1 forms antiparallel dimers, which further assemble into tetramers and higher-order oligomers in a concentration-dependent manner. Structure-based mutations in the B-box 1 domain prevent higher-order oligomerization without significant loss of retrotransposon silencing activity, indicating that, in contrast to other TRIM-family proteins, self-assembly is not essential for KAP1 function. The crystal structure of the KAP1 TRIM dimer identifies the KRAB domain binding site in the coiled-coil domain near the dyad. Mutations at this site abolished KRAB binding and transcriptional silencing activity of KAP1. This work identifies the interaction interfaces in the KAP1 TRIM responsible for self-association and KRAB binding and establishes their role in retrotransposon silencing.

A low-complexity region in the YTH domain protein Mmi1 enhances RNA binding.

Mmi1 is an essential RNA-binding protein in the fission yeast Schizosaccharomyces pombe that eliminates meiotic transcripts during normal vegetative growth. Mmi1 contains a YTH domain that binds specific RNA sequences, targeting mRNAs for degradation. The YTH domain of Mmi1 uses a noncanonical RNA-binding surface that includes contacts outside the conserved fold. Here, we report that an N-terminal extension that is proximal to the YTH domain enhances RNA binding. Using X-ray crystallography, NMR, and biophysical methods, we show that this low-complexity region becomes more ordered upon RNA binding. This enhances the affinity of the interaction of the Mmi1 YTH domain with specific RNAs by reducing the dissociation rate of the Mmi1-RNA complex. We propose that the low-complexity region influences RNA binding indirectly by reducing dynamic motions of the RNA-binding groove and stabilizing a conformation of the YTH domain that binds to RNA with high affinity. Taken together, our work reveals how a low-complexity region proximal to a conserved folded domain can adopt an ordered structure to aid nucleic acid binding.

Structure of subcomplex Iß of mammalian respiratory complex I leads to new supernumerary subunit assignments.

Mitochondrial complex I (proton-pumping NADH:ubiquinone oxidoreductase) is an essential respiratory enzyme. Mammalian complex I contains 45 subunits: 14 conserved "core" subunits and 31 "supernumerary" subunits. The structure of Bos taurus complex I, determined to 5-Å resolution by electron cryomicroscopy, described the structure of the mammalian core enzyme and allowed the assignment of 14 supernumerary subunits. Here, we describe the 6.8-Å resolution X-ray crystallography structure of subcomplex Iß, a large portion of the membrane domain of B. taurus complex I that contains two core subunits and a cohort of supernumerary subunits. By comparing the structures and composition of subcomplex Iß and complex I, supported by comparisons with Yarrowia lipolytica complex I, we propose assignments for eight further supernumerary subunits in the structure. Our new assignments include two CHCH-domain containing subunits that contain disulfide bridges between CX9C motifs; they are processed by the Mia40 oxidative-folding pathway in the intermembrane space and probably stabilize the membrane domain. We also assign subunit B22, an LYR protein, to the matrix face of the membrane domain. We reveal that subunit B22 anchors an acyl carrier protein (ACP) to the complex, replicating the LYR protein-ACP structural module that was identified previously in the hydrophilic domain. Thus, we significantly extend knowledge of how the mammalian supernumerary subunits are arranged around the core enzyme, and provide insights into their roles in biogenesis and regulation.

Novel pyrazoline derivatives as bi-inhibitor of COX-2 and B-Raf in treating cervical carcinoma.

Twenty four pyrazoline derivatives modified from Celecoxib were designed and synthesized as bi-inhibitor of COX-2 and B-Raf. They were evaluated for their COX-1/COX-2/B-Raf inhibitory and anti-proliferation activities. Compound A3 displayed the most potent activity against COX-2 and HeLa cell line (IC50=0.008 µM; GI50=19.86 µM) and showed superb COX-1/COX-2 selectivity (>500), being more potent and selective than positive control Celecoxib or 5-fluorouracil. Compounds A5 and B5 were introduced best B-Raf inhibitory activities (IC50=0.15 µM and 0.12 µM, respectively). Compound A4 retained superb bioactivity against COX-2 and HeLa cell line (IC50=0.015 µM; GI50=23.82 µM) and displayed moderate B-Raf inhibitory activity (IC50=3.84 µM). Docking simulation was conducted to give binding patterns. QSAR models were built using bioactivity data and optimized conformations to provide a future modification of COX-2/B-Raf inhibitors.

A case report and a literature review of double mammary pseudoangiomatous stromal hyperplasia associated with galactoma during pregnancy.

Pseudoangiomatous stromal hyperplasia (PASH) is a benign interstitial hyperplasia of the breast that usually occurs in premenopausal or perimenopausal women. It is usually characterized by localized lesions or clear boundary masses, and diffuse double breast enlargement is rare. PASH is considered a hormone-dependent disease that is commonly progesterone related. There are no imaging characteristics, and both benign and suspicious malignant signs can be seen. The definitive diagnosis of PASH depends on a pathological diagnosis, and it is necessary to be vigilant in distinguishing between benign and malignant tumors with similar breast histopathology. Here, we report the case of a 23-year-old multipara patient with bilateral diffuse pseudoangiomatous stromal hyperplasia of the breast during pregnancy who presented with macromastia and reviewed the literature to further understand the clinical features, pathological diagnosis, differential diagnosis, treatment and prognosis of pseudoangiomatous stromal hyperplasia of the breast.

Study on the Mechanism of Astragalus Polysaccharides on Cervical Cancer Based on Network Pharmacology.

BACKGROUND: Astragalus polysaccharides (APS) is a natural phytochemical which has been extensively utilized for anti-tumor therapy over the past few years. However, its impact on cervical cancer (CC) has rarely been studied. OBJECTIVE: To clarify the exact mechanism of anti-cancer effects of Astragalus polysaccharides (APS) on Cervical Cancer (CC), we screened differentially expressed genes (DEGs) from The Cancer Genome Atlas (TCGA) to construct the cancer network. METHODS: Then we performed functional enrichment analysis with gene ontology (GO) and KEGG pathway analyses, constructed protein-protein interaction (PPI) network, and performed molecular docking (MD) analysis to identify the key gene for docking with APS. Further, we observed the effects of APS on cell proliferation, cell cycle, and apoptosis experiments in HeLa cells. qRT-PCR and western blot were used to detect the expression of target genes. RESULTS: A total of 793 DEGs were screened using criteria, which included 541 genes that were upregulated and 251 genes that were down-regulated. Using topological attributes for identifying critical targets, molecular docking (MD), and survival analyses, this study predicted the APS targets: POLO-like kinase 1(PLK1), Cyclin-cell division 20(CDC20), and Cyclin-dependent kinase 1 (CDK1), which regulated HeLa cells. The results of cell proliferation, cell cycle, and apoptosis experiments concluded that APS inhibited the development of HeLa cells in a concentrationdependent manner. Also, qRT-PCR and western blot experiments demonstrated that APS could significantly down-regulate the expression of PLK1, CDC20, and CDK1 in the CC cells. CONCLUSION: The result revealed that APS might have a therapeutic potential in treating CC and might permit intervention with treatments targeting PLK1, CDC20, and CDK1.

Long Non-coding RNA UCA1a Promotes Proliferation via PKM2 in Cervical Cancer.

Cervical cancer is a common malignancy that affects women worldwide. The long non-coding RNA (lncRNA) urothelial cancer-associated 1a (UCA1a) is reported to be significantly upregulated in cervical cancer. However, the exact role of UCA1a in cervical cancer remains unknown. This study aimed to identify two core promoter regions in UCA1a, which are essential for CEBPA-dependent transcription and FOXL1-, FOXL4-, and FOXL6-dependent activation, respectively. RNA sequencing results showed that overexpression of UCA1a resulted in extensive changes in the gene expression profile of HeLa cells, especially in the signaling pathway that regulates tumorgenesis. Mass spectrometry assay was conducted to show that pyruvate kinase M2 (PKM2) was a UCA1a-interacting protein. The 400 ~ 800 nt long region of UCA1a at the 5' end and the A1B domain of PKM2 were critical for the UCA1a-PKM2 interaction. Functional assays were performed to show that PKM2 was sufficient and necessary for UCA1a-induced proliferation of HeLa cells, which was partly due to the regulating of nuclear translocation and stabilization of PKM2. These findings provide a novel mechanism for UCA1a to regulate Hela cells by ubiquitination degradation of PKM2 and suggest that UCA1a may play a key role in the progression of cervical cancer.

Ethylenediaminetetraacetic Acid-induced Pseudothrombocytopenia in Association with Graves' Hyperthyroidism.

Ethylenediaminetetraacetic acid-dependent pseudothrombocytopenia (EDTA-PTCP) is an in vitro phenomenon of EDTA-induced platelet aggregation. A number of mechanisms have been proposed to account for this phenomenon. EDTA-PTCP has been found in healthy subjects and patients with a variety of conditions, including viral infections, cardiovascular disease, liver disease, neoplastic diseases and autoimmune diseases. In the present case, a 66-year male had a 5-month history of palpitations. The patient presented with Graves' hyperthyroidism and was diagnosed with transient EDTA-PTCP. With the improvement of hyperthyroidism, the phenomenon of EDTA-PTCP disappeared. So far, EDTA-PTCP related to Graves' hyperthyroidism has not been reported in the literature. Key Words: Hyperthyroidism, Thrombocytopenia, Autoimmune diseases, Platelet aggregation, Edetic acid.

Andrographolide, a natural anti-inflammatory agent: An Update.

Botanicals have attracted much attention in the field of anti-inflammatory due to their good pharmacological activity and efficacy. Andrographis paniculata is a natural plant ingredient that is widely used around the world. Andrographolide is the main active ingredient derived from Andrographis paniculata, which has a good effect on the treatment of inflammatory diseases. This article reviews the application, anti-inflammatory mechanism and molecular targets of andrographolide in different inflammatory diseases, including respiratory, digestive, immune, nervous, cardiovascular, skeletal, and tumor system diseases. And describe its toxicity and explain its safety. Studies have shown that andrographolide can be used to treat inflammatory lesions of various systemic diseases. In particular, it acts on many inflammation-related signalling pathways. The future direction of andrographolide research is also introduced, as is the recent research that indicates its potential clinical application as an anti-inflammatory agent.

Upregulation of Ferroptosis-Related Fanconi Anemia Group D2 is a Poor Prognostic Factor and an Indicator of Tumor Immune Cell Infiltration in Lung Adenocarcinoma.

Fanconi anemia (FA) group D2 (FANCD2) is a ferroptosis-related gene crucial for DNA damage repair and negative ferroptosis regulation. Our study aimed to evaluate its prognostic value as well as its association with ferroptosis and immune infiltration in lung adenocarcinoma (LUAD). Transcriptome sequencing data, clinical information, and immunohistochemistry data were collected from the TCGA, GEO, and HPA databases, respectively, for three independent cohorts. Univariate and multivariate analyses were used to assess the correlations between FANCD2 expression and overall survival or clinicopathological parameters. cBioPortal was utilized to investigate the FANCD2 alteration status. Gene and protein networks based on FANCD2 interactions were generated using GeneMANIA and STRING, respectively. Based on the CancerSEA database, the function of FANCD2 was explored at the single-cell level. The relationships between FANCD2 expression levels and tumor-infiltrating immune cells and their equivalent gene signatures were analyzed using TIMER, GEPIA, TISIDB, and ssGSEA databases. CIBERSORT was used to analyze the relevance of the infiltration of 24 types of immune cells. The results revealed that FANCD2 expression was significantly upregulated in LUAD and lung squamous cell carcinoma (LUSC) tissues than that in normal tissues. Further, the overexpression of FANCD2 was closely associated with poor survival for Patients with LUAD but not for patients with LUSC. FANCD2 expression levels were related to tumor-infiltrating immune cells and their matching gene signatures, including CD8+ T cells, natural killer (NK) cells, dendritic cells (DC), and Th2 cells in cases of LUAD. Therefore, FANCD2 was identified as a crucial molecule underlying the synergistic effects of ferroptosis and immunotherapy for Patients with LUAD.

Crystal structures of BMPRII extracellular domain in binary and ternary receptor complexes with BMP10.

Heterozygous mutations in BMPR2 (bone morphogenetic protein (BMP) receptor type II) cause pulmonary arterial hypertension. BMPRII is a receptor for over 15 BMP ligands, but why BMPR2 mutations cause lung-specific pathology is unknown. To elucidate the molecular basis of BMP:BMPRII interactions, we report crystal structures of binary and ternary BMPRII receptor complexes with BMP10, which contain an ensemble of seven different BMP10:BMPRII 1:1 complexes. BMPRII binds BMP10 at the knuckle epitope, with the A-loop and ß4 strand making BMPRII-specific interactions. The BMPRII binding surface on BMP10 is dynamic, and the affinity is weaker in the ternary complex than in the binary complex. Hydrophobic core and A-loop interactions are important in BMPRII-mediated signalling. Our data reveal how BMPRII is a low affinity receptor, implying that forming a signalling complex requires high concentrations of BMPRII, hence mutations will impact on tissues with highest BMPR2 expression such as the lung vasculature.

The relationship between MHC-peptide interaction and resistance to virus in chickens.

INTRODUCTION: The MHC-peptide interaction has a subtle influence on host resistance to virus. This paper aims to study the relationship between MHC-peptide interaction and MHC-related virus-resistance. METHODS: By 3D homology modeling, the structure of chicken BF2 molecule BF2*0201 (PDB code: 4d0d) was studied and compared with the known structures of BF2 molecule BF2*0401 (PDB code: 4e0r) to elucidate the characteristics of BF2*0201-binding antigenic peptides. RESULTS: The results show that due to the amino acid difference between the two binding groove of 4e0r and 4d0d, the size of the binding groove of the two are 1130 ų and1380 ų respectively, indicating the amino acid species that 4e0r binding peptide has lower selectivity than 4d0d; and because of large side chain conformation of Arg (especially Arg111) of 4e0r replaced by small side chain Tyr111 of 4d0d, the volume of central part of the binding groove of 4d0d is obviously larger than that of 4e0r, indicating that the restrictive of binding antigenic peptides for 4d0d is narrower than that of 4e0r; and on account of the chargeability of the binding groove of the two are different, namely the binding groove chargeability of 4e0r (strong positive polarity) and 4d0d (weak negative polarity). CONCLUSION: There are generally more peptides presented by the BF2 of B2 haplotype than by that of B4 haplotype, leading to more resistance of B2 than that of B4 to virus.

Expression, purification and preliminary crystallographic analysis of O-acetylhomoserine sulfhydrylase from Mycobacterium tuberculosis.

The gene product of the open reading frame Rv3340 from Mycobacterium tuberculosis is annotated as encoding a probable O-acetylhomoserine (OAH) sulfhydrylase (MetC), an enzyme that catalyzes the last step in the biosynthesis of methionine, which is an essential amino acid in bacteria and plants. Following overexpression in Escherichia coli, the M. tuberculosis MetC enzyme was purified and crystallized using the hanging-drop vapor-diffusion method. Native diffraction data were collected from crystals belonging to space group P2(1) and were processed to a resolution of 2.1 Å.

An Adrenal Incidentaloma Diagnosed as Dopamine-Secreting Pheochromocytoma: A Case Report.

BACKGROUND: Dopamine-secreting pheochromocytomas are exceedingly rare. CASE PRESENTATION: A 28-year-old woman, who was admitted due to 4 hours of acute-onset abdominal pain, detected an adrenal mass incidentally. She was almost asymptomatic without a known family history. Laboratory assessments showed significant increases in dopamine levels of serum and 24-h urinary. By using preoperative a-adrenergic receptor blockers, she developed orthostatic hypotension and palpitations. When she underwent laparoscopic left adrenalectomy, she experienced rapid cyclic fluctuations in systolic blood pressure from 90 mmHg to 200 mmHg. Postoperatively, she exhibited prolonged hypotension, requiring vasopressor therapy and fluid replacement. According to histopathological diagnosis, it was a pheochromocytoma. Dopamine levels in 24-h urine and serum decreased to normal after operation. Analysis of specific gene SDHB, SDHD, RET, VHL and NF1 detected no pathogenic mutations. CONCLUSION: Patients with dopamine-secreting pheochromocytomas are mostly asymptomatic, leading to a significant delay in diagnosis. There is a large possibility for dopamine-secreting pheochromocytomas to show a malignant tendency than the adrenergic and noradrenergic phenotypes. The a-adrenergic receptor blocker is not indicated for preoperative medical treatment because it can cause hypotension and cardiovascular failure. Calcium channel blockers or metyrosine may be better alternatives. All patients with pheochromocytomas should receive targeted genetic testing based on specific clinical features. SDHB, SDHD, RET, VHL and NF1 mutations are suggested for genetic testing of adrenal dopamine-secreting pheochromocytomas.

Study on the contrast of the MHC-peptide interaction of B2/B21 haplotype and MHC-related virus resistance in chickens.

INTRODUCTION: Three-dimensional (3D) structures of MHC class I exert some influence by the MHC-peptide interaction over host resistance to the virus. The thesis aims at studying the connection between MHC-peptide interaction of B2/B21 haplotype and MHC-related resistance to the virus. METHODS: The structure of chicken MHC class I BF2*0201 from B2 haplotype was studied and contrasted with that of BF2*2101 from B21 haplotype by using DNAMAN and PyMol software. RESULTS: The amino acid difference resulted in the difference in size and changeability of the binding groove of the two, resulting in different choices on the binding polypeptide. 3bew's (the crystal structure of BF2*2101 bound to peptide RV10) small side chain His111 replaces the short side chain Tyr111 of 4cvx (the crystal structure of BF2*0201 bound to peptide YL9), and the very small amino acid of Ser69 and Ser97 make the middle of the 3bew's binding groove become apparently broad and bound restrictive of amino acid smaller. Moreover, due to the specific amino acids-Arg9, Asp24, and Asp73 of 4cvx and Arg9, Asp24, and His111 of 3bew, the effect of the polypeptide and the binding groove differ between the two, and 3bew tends to bind polypeptides with negatively charged amino acids, but the large space in the middle can also accommodate other amino acids. Contrasted with the binding groove characteristic of 4cvx, it can be said that the selectivity of 3bew is higher than that of 4cvx in the amino acid type of the binding polypeptide, so the B21 haplotype has more host resistance to the virus than that of the B2 haplotype in chicken. CONCLUSION: There are usually various kinds of peptides presented by the BF2*2101 molecules of B21 haplotypes, resulting in resistance to pathogenic microorganisms, such as Rous sarcoma virus and/or Marek's disease virus. These findings may have an important theoretical foundation for screening of virus antigen, vaccine design, and genetic resistance breeding.

MicroRNA-373-3p inhibits the growth of cervical cancer by targeting AKT1 both in vitro and in vivo.

OBJECTIVE: In this study, we aimed to investigate the function of microRNA-373-3p (miR-373-3p) in the pathogenesis of cervical cancer. METHODS: Human and mouse cervical cancer cell lines were transfected with miR-373-3p mimic and inhibitor. Cell proliferation and viability were evaluated with Cell Counting Kit-8 (CCK-8) assay and Lactate Dehydrogenase (LDH) assay, respectively. The AKT1-targeting role of miR-373-3p was analyzed by qPCR and Western blot. Finally, a mouse xenograft cervical tumor model was adopted to study the in vivo effect of miR-373-3p on tumor growth and the expression of AKT1. RESULTS: Over-expression of miR-373-3p significantly reduced the proliferation of cervical carcinoma cell line in vitro. In addition, miR-373-3p overexpression also inhibited cervical cancer growth in tumor-bearing mice. Mechanistically, we found that AKT1 gene can be targeted by miR-373-3p. MiR-373-3p mimic decreased the mRNA and protein expression of AKT1, while the miR-373-3p inhibitor increased the level of AKT1 in cervical cancer cells. AKT1 overexpression rescued the proliferation of cervical cancer cells transfected with miR-373-3p. CONCLUSION: MiR-373-3p can serve as a novel anti-tumor microRNA in cervical cancer by targeting AKT1.

Molecular basis of ALK1-mediated signalling by BMP9/BMP10 and their prodomain-bound forms.

Activin receptor-like kinase 1 (ALK1)-mediated endothelial cell signalling in response to bone morphogenetic protein 9 (BMP9) and BMP10 is of significant importance in cardiovascular disease and cancer. However, detailed molecular mechanisms of ALK1-mediated signalling remain unclear. Here, we report crystal structures of the BMP10:ALK1 complex at 2.3 Å and the prodomain-bound BMP9:ALK1 complex at 3.3 Å. Structural analyses reveal a tripartite recognition mechanism that defines BMP9 and BMP10 specificity for ALK1, and predict that crossveinless 2 is not an inhibitor of BMP9, which is confirmed by experimental evidence. Introduction of BMP10-specific residues into BMP9 yields BMP10-like ligands with diminished signalling activity in C2C12 cells, validating the tripartite mechanism. The loss of osteogenic signalling in C2C12 does not translate into non-osteogenic activity in vivo and BMP10 also induces bone-formation. Collectively, these data provide insight into ALK1-mediated BMP9 and BMP10 signalling, facilitating therapeutic targeting of this important pathway.

Analysis of nucleoside-binding proteins by ligand-specific elution from dye resin: application to Mycobacterium tuberculosis aldehyde dehydrogenases.

We show that Cibacron Blue F3GA dye resin chromatography can be used to identify ligands that specifically interact with proteins from Mycobacterium tuberculosis, and that the identification of these ligands can facilitate structure determination by enhancing the quality of crystals. Four native Mtb proteins of the aldehyde dehydrogenase (ALDH) family were previously shown to be specifically eluted from a Cibacron Blue F3GA dye resin with nucleosides. In this study we characterized the nucleoside-binding specificity of one of these ALDH isozymes (recombinant Mtb Rv0223c) and compared these biochemical results with co-crystallization experiments with different Rv0223c-nucleoside pairings. We found that the strongly interacting ligands (NAD and NADH) aided formation of high-quality crystals, permitting solution of the first Mtb ALDH (Rv0223c) structure. Other nucleoside ligands (AMP, FAD, adenosine, GTP and NADP) exhibited weaker binding to Rv0223c, and produced co-crystals diffracting to lower resolution. Difference electron density maps based on crystals of Rv0223c with various nucleoside ligands show most share the binding site where the natural ligand NAD binds. From the high degree of similarity of sequence and structure compared to human mitochondrial ALDH-2 (BLAST Z-score = 53.5 and RMSD = 1.5 A), Rv0223c appears to belong to the ALDH-2 class. An altered oligomerization domain in the Rv0223c structure seems to keep this protein as monomer whereas native human ALDH-2 is a multimer.