PDBsum entry 5b7c

Structural protein

PDB id: 5b7c

Contents

Protein chain

206 a.a.

Ligands

GSH

SO4

Waters ×44

PDB id:

5b7c

Name:

Structural protein

Title:

Crystal structure of octopus s-crystallin q108f mutant in complex with glutathione

Structure:

S-crystallin octvus4. Chain: a. Engineered: yes

Source:

Octopus vulgaris. Common octopus. Organism_taxid: 6645. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.35Å R-factor: 0.195 R-free: 0.250

Authors:

C.-Y.Chou,W.-H.Tan,C.-G.Wu

Key ref:

W.H.Tan et al. (2016). Structure of a Highly Active Cephalopod S-crystallin Mutant: New Molecular Evidence for Evolution from an Active Enzyme into Lens-Refractive Protein. Sci Rep, 6, 31176. PubMed id: 27499004 DOI: 10.1038/srep31176

Date:

07-Jun-16 Release date: 03-Aug-16

Protein chain

A0A1C7D1H4  (A0A1C7D1H4_OCTVU) -  S-crystallin OctvuS4 from Octopus vulgaris

Seq: 215 a.a.

Struc: 206 a.a.

DOI no: 10.1038/srep31176

Sci Rep 6:31176 (2016)

PubMed id: 27499004

Structure of a Highly Active Cephalopod S-crystallin Mutant: New Molecular Evidence for Evolution from an Active Enzyme into Lens-Refractive Protein.

W.H.Tan, S.C.Cheng, Y.T.Liu, C.G.Wu, M.H.Lin, C.C.Chen, C.H.Lin, C.Y.Chou.

ABSTRACT

Crystallins are found widely in animal lenses and have important functions due to their refractive properties. In the coleoid cephalopods, a lens with a graded refractive index provides good vision and is required for survival. Cephalopod S-crystallin is thought to have evolved from glutathione S-transferase (GST) with various homologs differentially expressed in the lens. However, there is no direct structural information that helps to delineate the mechanisms by which S-crystallin could have evolved. Here we report the structural and biochemical characterization of novel S-crystallin-glutathione complex. The 2.35-Å crystal structure of a S-crystallin mutant from Octopus vulgaris reveals an active-site architecture that is different from that of GST. S-crystallin has a preference for glutathione binding, although almost lost its GST enzymatic activity. We've also identified four historical mutations that are able to produce a "GST-like" S-crystallin that has regained activity. This protein recapitulates the evolution of S-crystallin from GST. Protein stability studies suggest that S-crystallin is stabilized by glutathione binding to prevent its aggregation; this contrasts with GST-σ, which do not possess this protection. We suggest that a tradeoff between enzyme activity and the stability of the lens protein might have been one of the major driving force behind lens evolution.