1w6k
Structure of human OSC in complex with Lanosterol
Structural highlights
DiseaseLSS_HUMAN Total early-onset cataract;Alopecia-intellectual disability syndrome;Hypotrichosis simplex. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. FunctionLSS_HUMAN Key enzyme in the cholesterol biosynthesis pathway. Catalyzes the cyclization of (S)-2,3 oxidosqualene to lanosterol, a reaction that forms the sterol nucleus (PubMed:14766201, PubMed:7639730, PubMed:26200341). Through the production of lanosterol may regulate lens protein aggregation and increase transparency (PubMed:26200341).[1] [2] [3] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedIn higher organisms the formation of the steroid scaffold is catalysed exclusively by the membrane-bound oxidosqualene cyclase (OSC; lanosterol synthase). In a highly selective cyclization reaction OSC forms lanosterol with seven chiral centres starting from the linear substrate 2,3-oxidosqualene. Valuable data on the mechanism of the complex cyclization cascade have been collected during the past 50 years using suicide inhibitors, mutagenesis studies and homology modelling. Nevertheless it is still not fully understood how the enzyme catalyses the reaction. Because of the decisive role of OSC in cholesterol biosynthesis it represents a target for the discovery of novel anticholesteraemic drugs that could complement the widely used statins. Here we present two crystal structures of the human membrane protein OSC: the target protein with an inhibitor that showed cholesterol lowering in vivo opens the way for the structure-based design of new OSC inhibitors. The complex with the reaction product lanosterol gives a clear picture of the way in which the enzyme achieves product specificity in this highly exothermic cyclization reaction. Insight into steroid scaffold formation from the structure of human oxidosqualene cyclase.,Thoma R, Schulz-Gasch T, D'Arcy B, Benz J, Aebi J, Dehmlow H, Hennig M, Stihle M, Ruf A Nature. 2004 Nov 4;432(7013):118-22. PMID:15525992[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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