Glutathione S-transferase and S-crystallins of cephalopods: Evolution from active enzyme to lens-refractive proteins

✍ Scribed by Stanislav I. Tomarev; Sambath Chung; Joram Piatigorsky

• Book ID: 104651285
• Publisher: Springer
• Year: 1995
• Tongue: English
• Weight: 917 KB
• Volume: 41
• Category: Article
• ISSN: 0022-2844
• DOI: 10.1007/bf00173186

✦ Synopsis

Our previous studies have shown that the S-crystallins of cephalopod ( Ommastrephes sloani pacificus) eye lenses comprise a family of at least ten members which are evolutionarily related to glutathione S-transferase (GST, EC 2.5.1.18). Here we show by cDNA cloning that there are at least 24 different S-crystallins that are 46-99% identical to each other by amino acid sequence in the squid Loligo opalescens. In each species, all but one S-crystallin (SL11 in O. pacificus and Lops4 in L. opalescens) examined has an inserted central peptide of variable length and sequence, cDNA expression studies conducted in Escherichia coli showed that squid GST (which is expressed little in the lens) has very high enzymatic activity using 1-chloro-2, 4-dinitrobenzene (CDNB) as a substrate; by contrast, SL20-1 of O.