The Role of Intrinsically Disordered Regions in the Structure and Functioning of Small Heat Shock Proteins

Title: The Role of Intrinsically Disordered Regions in the Structure and Functioning of Small Heat Shock Proteins

Volume: 13 Issue: 1

Author(s): Maria V. Sudnitsyna, Evgeny V. Mymrikov, Alim S. Seit-Nebi and Nikolai B. Gusev

Affiliation:

Keywords: Intrinsic disorder, protein-protein interaction, phosphorylation, small heat shock proteins, sHsp, DNAJ, axonopodis, Methanococcus jannaschii, Xanthomonas, HspA

Abstract: Small heat shock proteins (sHsp) form a large ubiquitous family of proteins expressed in all phyla of living organisms. The members of this family have low molecular masses (13-43 kDa) and contain a conservative α-crystallin domain. This domain (about 90 residues) consists of several β-strands forming two β-sheets packed in immunoglobulinlike manner. The α-crystallin domain plays an important role in formation of stable sHsp dimers, which are the building blocks of the large sHsp oligomers. A large N-terminal domain and a short C-terminal extension flank the α-crystallin domain. Both the N-terminal domain and the C-terminal extension are flexible, susceptible to proteolysis, prone to posttranslational modifications, and are predominantly intrinsically disordered. Differently oriented N-terminal domains interact with each other, with the core α-crystallin domain of the same or neighboring dimers and play important role in formation of large sHsp oligomers. Phosphorylation of certain sites in the N-terminal domain affects the sHsp quaternary structure, the sHsp interaction with target proteins and the sHsp chaperone-like activity. The C-terminal extension often carrying the conservative tripeptide (I/V/L)-X-(I/V/L) is capable of binding to a hydrophobic groove on the surface of the core α-crystallin domain of neighboring dimer, thus affecting the plasticity and the overall structure of sHsp oligomers. The Cterminal extension interacts with target proteins and affects their interaction with the α-crystallin domain increasing solubility of the complexes formed by sHsp and their targets. Thus, disordered N- and C-terminal sequences play important role in the structure, regulation and functioning of sHsp.

Cite this article as:

V. Sudnitsyna Maria, V. Mymrikov Evgeny, S. Seit-Nebi Alim and B. Gusev Nikolai, The Role of Intrinsically Disordered Regions in the Structure and Functioning of Small Heat Shock Proteins, Current Protein & Peptide Science 2012; 13 (1) . https://dx.doi.org/10.2174/138920312799277875