Download MendeleyLengsin 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, H.E., Wang, L., Bateman, O.A., Slingsby, C., Orlova, E.V., Wistow, G.(2006) Structure 14: 1823
- PubMed: 17161372
- DOI: https://doi.org/10.1016/j.str.2006.10.008
- Primary Citation of Related Structures:
2J9I - PubMed Abstract:
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.
Organizational Affiliation:
Section on Molecular Structure and Functional Genomics, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
