title: Cis/trans heterogeneity of Gln30-Pro31 peptide bond determines whether a 79-residue fragment of staphylococcal nuclease self-associates.
abstract: The self-association reaction of a 79-residue fragment of staphylococcal nuclease (SNase79) was studied by far-UV CD, size-exclusion chromatography, and heteronuclear multidimensional NMR spectroscopy. A large population of SNase79 is in self-associated state while a small population of SNase79 is essentially in a monomeric state. The sequence region Thr13-Val39 is responsible for association interface of SNase79. The trans-conformation of X-prolyl bond Gln30-Pro31 may make residues Tyr27-Gln30, serve as a folding nucleation site, and lead the segment Thr13-Val39 of SNase79 to adopt a native-like beta-sheet conformation, which results in the self-association of SNase79. The non-native conformation of the segment Thr13-Val39 of SNase79 associated with the cis-conformation of X-prolyl bond Gln30-Pro31 may preclude SNase79 from the soluble aggregates.
authors.affiliation: National Laboratory of Biomacromolecules, Center for Structural and Molecular Biology, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Wang
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Tong
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Wang
mesh_terms: D019943:Amino Acid Substitution; D000596:Amino Acids / Q000737:chemistry*; D001665:Binding Sites; D004789:Enzyme Activation; D007536:Isomerism; D008836:Micrococcal Nuclease / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D013329:Structure-Activity Relationship
chemical_list: D000596:Amino Acids; D010455:Peptides; D008836:Micrococcal Nuclease