title: Detection of oligomerisation and substrate recognition sites of small heat shock proteins by peptide arrays.
abstract: Small heat shock proteins (sHsps) form large oligomers that are characterised by their dynamic behaviour, e.g., complex disassembly/reassembly and extensive subunit exchange. These processes are interrelated with sHsp/substrate interaction. sHsps bind a broad spectrum of unrelated substrate proteins under denaturing conditions. Detailed knowledge about the binding process and regions critical for sHsp/substrate interaction is missing. In this study, we screened cellulose-bound peptide spot libraries derived from a bacterial sHsp and the model-substrate citrate synthase to detect oligomerisation and substrate interaction sites, respectively. In line with previous results, it was demonstrated that multiple contacts involving the N- and C-terminal extensions and the central alpha-crystallin domain are required for oligomerisation. Incubation of the citrate synthase membrane with sHsps revealed a putative substrate interaction site. A soluble peptide with the sequence RTKYWELIYEDCMDL (CS(191-205)) corresponding to that site inhibited chaperone activity of sHsps, presumably by blocking their substrate-binding sites.
authors.affiliation: Institut für Mikrobiologie, Eidgenössische Technische Hochschule, CH-8092 Zürich, Switzerland.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Lentze
authors.forename: Franz
authors.initials: F
authors.lastname: Narberhaus
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002482:Cellulose / Q000378:metabolism; D002950:Citrate (si)-Synthase / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006358:Hot Temperature; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D019151:Peptide Library; D010449:Peptide Mapping / Q000379:methods; D040081:Protein Array Analysis / Q000379:methods; D011485:Protein Binding; D011487:Protein Conformation; D011489:Protein Denaturation; D017434:Protein Structure, Tertiary; D013379:Substrate Specificity; D038201:alpha-Crystallins / Q000737:chemistry / Q000378:metabolism
chemical_list: D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D019151:Peptide Library; D038201:alpha-Crystallins; D002482:Cellulose; D002950:Citrate (si)-Synthase