Crystal Structure of 12-Lipoxygenase Catalytic-Domain-Inhibitor Complex Identifies a Substrate-Binding Channel for Catalysis

Sialidase catalyzes the removal of a terminal sialic acid from glycoconjugates and plays a pivotal role in nutrition, cellular interactions and pathogenesis mediating various infectious diseases including cholera, influenza and sepsis. An array of antiviral sialidase agents have been developed and are commercially available, such as zanamivir and oseltamivir for treating influenza. However, the development of bacterial sialidase inhibitors has been much less successful. Here, natural polyphenolic geranylated flavonoids which show significant inhibitory effects againstCp-NanI, a sialidase fromClostridium perfringens, are reported. This bacterium causes various gastrointestinal diseases. The crystal structure of theCp-NanI catalytic domain in complex with the best inhibitor, diplacone, is also presented. This structure explains how diplacone generates a stable enzyme–inhibitor complex. These results provide a structural framework for understanding the interaction between sialidase and natural flavonoids, which are promising scaffolds on which to discover new anti-sialidase agents.

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Faculty Opinions recommendation of The crystal structure of human alpha1-tryptase reveals a blocked substrate-binding region.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1009789.135416 ◽

2002 ◽

Author(s):

Patricia C Weber

Keyword(s):

Crystal Structure ◽

Substrate Binding ◽

Binding Region

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Faculty Opinions recommendation of Transcarboxylase 12S crystal structure: hexamer assembly and substrate binding to a multienzyme core.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1014069.192707 ◽

2003 ◽

Author(s):

Wolfgang Buckel

Keyword(s):

Crystal Structure ◽

Substrate Binding

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Faculty Opinions recommendation of Crystal structure of the human lymphoid tyrosine phosphatase catalytic domain: insights into redox regulation .

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1162316.622811 ◽

2009 ◽

Author(s):

Amy Barrios

Keyword(s):

Crystal Structure ◽

Redox Regulation ◽

Catalytic Domain ◽

Tyrosine Phosphatase

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Crystal structure of steroid reductase SRD5A reveals conserved steroid reduction mechanism

Nature Communications ◽

10.1038/s41467-020-20675-2 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Yufei Han ◽

Qian Zhuang ◽

Bo Sun ◽

Wenping Lv ◽

Sheng Wang ◽

...

Keyword(s):

Crystal Structure ◽

Biochemical Characterization ◽

Substrate Binding ◽

Binding Pocket ◽

Substrate Binding Pocket ◽

Transmembrane Segments ◽

Therapeutic Molecules ◽

Binding Cavity ◽

Immune System Regulation ◽

Mediated Reduction

AbstractSteroid hormones are essential in stress response, immune system regulation, and reproduction in mammals. Steroids with 3-oxo-Δ4 structure, such as testosterone or progesterone, are catalyzed by steroid 5α-reductases (SRD5As) to generate their corresponding 3-oxo-5α steroids, which are essential for multiple physiological and pathological processes. SRD5A2 is already a target of clinically relevant drugs. However, the detailed mechanism of SRD5A-mediated reduction remains elusive. Here we report the crystal structure of PbSRD5A from Proteobacteria bacterium, a homolog of both SRD5A1 and SRD5A2, in complex with the cofactor NADPH at 2.0 Å resolution. PbSRD5A exists as a monomer comprised of seven transmembrane segments (TMs). The TM1-4 enclose a hydrophobic substrate binding cavity, whereas TM5-7 coordinate cofactor NADPH through extensive hydrogen bonds network. Homology-based structural models of HsSRD5A1 and -2, together with biochemical characterization, define the substrate binding pocket of SRD5As, explain the properties of disease-related mutants and provide an important framework for further understanding of the mechanism of NADPH mediated steroids 3-oxo-Δ4 reduction. Based on these analyses, the design of therapeutic molecules targeting SRD5As with improved specificity and therapeutic efficacy would be possible.

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The first crystal structure of the peptidase domain of the U32 peptidase family

Acta Crystallographica Section D Biological Crystallography ◽

10.1107/s1399004715019549 ◽

2015 ◽

Vol 71 (12) ◽

pp. 2505-2512 ◽

Cited By ~ 4

Author(s):

Magdalena Schacherl ◽

Angelika A. M. Montada ◽

Elena Brunstein ◽

Ulrich Baumann

Keyword(s):

Crystal Structure ◽

Catalytic Mechanism ◽

Quaternary Structure ◽

Catalytic Domain ◽

Three Dimensional ◽

Zinc Ion ◽

Crystal Structure Analysis ◽

Dimensional Structure ◽

Sequence Motifs ◽

Conserved Sequence

The U32 family is a collection of over 2500 annotated peptidases in the MEROPS database with unknown catalytic mechanism. They mainly occur in bacteria and archaea, but a few representatives have also been identified in eukarya. Many of the U32 members have been linked to pathogenicity, such as proteins fromHelicobacterandSalmonella. The first crystal structure analysis of a U32 catalytic domain fromMethanopyrus kandleri(genemk0906) reveals a modified (βα)8TIM-barrel fold with some unique features. The connecting segment between strands β7 and β8 is extended and helix α7 is located on top of the C-terminal end of the barrel body. The protein exhibits a dimeric quaternary structure in which a zinc ion is symmetrically bound by histidine and cysteine side chains from both monomers. These residues reside in conserved sequence motifs. No typical proteolytic motifs are discernible in the three-dimensional structure, and biochemical assays failed to demonstrate proteolytic activity. A tunnel in which an acetate ion is bound is located in the C-terminal part of the β-barrel. Two hydrophobic grooves lead to a tunnel at the C-terminal end of the barrel in which an acetate ion is bound. One of the grooves binds to aStrep-Tag II of another dimer in the crystal lattice. Thus, these grooves may be binding sites for hydrophobic peptides or other ligands.

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