1. Solution NMR structure and ligand identification of human Gas7 SH3 domain reveal a typical SH3 fold but a non-canonical ligand-binding mode
- Author
-
M.A. Kennedy, Yunhuang Yang, Theresa Ramelot, Jiang Zhu, Ting He, Yao Nie, and Maili Liu
- Subjects
Models, Molecular ,0301 basic medicine ,Gene isoform ,Protein Folding ,animal structures ,Phage display ,Stereochemistry ,Structural similarity ,Biophysics ,Nerve Tissue Proteins ,Peptide ,macromolecular substances ,Ligands ,environment and public health ,Biochemistry ,SH3 domain ,src Homology Domains ,03 medical and health sciences ,0302 clinical medicine ,Humans ,Amino Acid Sequence ,Peptide library ,Nuclear Magnetic Resonance, Biomolecular ,Molecular Biology ,chemistry.chemical_classification ,Binding Sites ,ABL ,Chemistry ,Cell Biology ,Ligand (biochemistry) ,030104 developmental biology ,030220 oncology & carcinogenesis ,Peptides ,Sequence Alignment ,Protein Binding - Abstract
Growth arrest specific 7 (Gas7) protein is a cytoskeleton regulator playing a crucial role in neural cell development and function, and has been implicated in Alzheimer disease, schizophrenia and cancers. In human, three Gas7 isoforms can be expressed from a single Gas7 gene, while only the longest isoform, hGas7c, possesses an SH3 domain at the N-terminus. To date, the structure and function of hGas7 SH3 domain are still unclear. Here, we reported the solution NMR structure of hGas7 SH3 domain (hGas7-SH3), which displays a typical SH3 β-barrel fold comprising five β-strands and one 310-helix. Structural and sequence comparison showed that hGas7-SH3 shares high similarity with Abl SH3 domain, which binds to a high-affinity proline-rich peptide P41 in a canonical SH3-ligand binding mode through two hydrophobic pockets and a specificity site in the RT-loop. However, unlike Abl-SH3, only six residues in the RT-loop and two residues adjacent to but not in the two hydrophobic pockets of hGas7-SH3 showed significant chemical shift perturbations in NMR titrations, suggesting a low affinity and a non-canonical binding mode of hGas7-SH3 for P41. Furthermore, four peptides selected from phage-displayed libraries also bound weakly to hGas7-SH3, and the binding region of hGas7-SH3 was mainly located in the RT-loop as well. The ligand identifications through structural similarity searching and peptide library screening in this study imply that although hGas7-SH3 adopts a typical SH3 fold, it probably possesses distinctive ligand-binding specificity.
- Published
- 2019