tailieunhanh - Báo cáo y học: " Reduced reliance on the trace element selenium during evolution of mammal"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Critical Care giúp cho các bạn có thêm kiến thức về ngành y học đề tài: Reduced reliance on the trace element selenium during evolution of mammals. | Open Access Reduced reliance on the trace element selenium during evolution of mammals Alexey V Lobanov Dolph L Hatfield and Vadim N Gladyshev Addresses Department of Biochemistry University of Nebraska Lincoln NE 68588 USA. Section on the Molecular Biology of Selenium Laboratory of Cancer Prevention National Cancer Institute National Institutes of Health Bethesda MD 20892 USA. Correspondence Vadim N Gladyshev. Email vgladyshev1@ Published 31 March 2008 Genome Biology 2008 9 R62 doi 186 gb-2008-9-3-r62 The electronic version of this article is the complete one and can be found online at http 2008 9 3 R62 Received 10 January 2008 Revised 5 March 2008 Accepted 31 March 2008 2008 Lobanov et al. licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License http licenses by which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. Abstract Background Selenium Se is an essential trace element that occurs in proteins in the form of selenocysteine Sec . It is transported throughout the body in the form of Sec residues in Selenoprotein P SelP a plasma protein of unclear origin recently proposed as an experimental marker of dietary Se status. Results Here we report that the amino-terminal domain of SelP is distantly related to ancestral bacterial thiol oxidoreductases of the thioredoxin superfamily and that its carboxy-terminal Se transport domain may have originated in early metazoan evolution by de novo accumulation of Sec residues. Reconstruction of evolutionary changes in the Se transport domain indicates a decrease in Sec content of SelP specifically in the mammalian lineage via replacement of Sec with cysteine Cys . Sec content of mammalian SelPs varies more than two-fold and is lowest in rodents and primates. Compared to mammals fish show higher Sec content of SelP larger .