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2j9i
From Proteopedia
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LENGSIN IS A SURVIVOR OF AN ANCIENT FAMILY OF CLASS I GLUTAMINE SYNTHETASES IN EUKARYOTES THAT HAS UNDERGONE EVOLUTIONARY RE-ENGINEERING FOR A TISSUE-SPECIFIC ROLE IN THE VERTEBRATE EYE LENS.
Overview
Lengsin is a major protein of the vertebrate eye lens. It belongs to the hitherto purely prokaryotic GS I branch of the glutamine synthetase (GS) superfamily, but has no enzyme activity. Like the taxon-specific crystallins, Lengsin is the result of the recruitment of an ancient enzyme to a noncatalytic role in the vertebrate lens. Cryo-EM and modeling studies of Lengsin show a dodecamer structure with important similarities and differences with prokaryotic GS I structures. GS homology regions of Lengsin are well conserved, but the N-terminal domain shows evidence of dynamic evolutionary changes. Compared with birds and fish, most mammals have an additional exon corresponding to part of the N-terminal domain; however, in human, this is a nonfunctional pseudoexon. Genes related to Lengsin are also present in the sea urchin, suggesting that this branch of the GS I family, supplanted by GS II enzymes in vertebrates, has an ancient role in metazoans.
About this Structure
2J9I is a Single protein structure of sequence from Mus musculus. Full crystallographic information is available from OCA.
Reference
Lengsin is a survivor of an ancient family of class I glutamine synthetases re-engineered by evolution for a role in the vertebrate lens., Wyatt K, White HE, Wang L, Bateman OA, Slingsby C, Orlova EV, Wistow G, Structure. 2006 Dec;14(12):1823-34. PMID:17161372
Page seeded by OCA on Thu Feb 21 18:00:44 2008
