Mutational Analysis of the Absolutely Conserved B8Gly: Consequence on Foldability and Activity of Insulin
Mutational Analysis of the Absolutely Conserved B8Gly: Consequence on Foldability and Activity of Insulin作者机构：Key Laboratory of Proteomics Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of SciencesShanghai 200031 China Institute of Biochemistry Zhejiang Sci-Tech UniversityHangzhou 310018 China
出 版 物：《Acta Biochimica et Biophysica Sinica》 (生物化学与生物物理学报(英文版))
年 卷 期：2005年第37卷第10期
页 面：673-679页
核心收录：
学科分类：0710[理学-生物学] 0831[工学-生物医学工程（可授工学、理学、医学学位）] 1001[医学-基础医学(可授医学、理学学位)] 0703[理学-化学] 10[医学]
主 题：insulin foldability activity disulfide stability
摘 要：B8Gly is absolutely conserved in insulins during ***,its correspondingposition is always occupied by a Gly residue in other members of insulin *** work showedthat Ala replacement of BSGly significantly decreased both the activity and the foldability of *** effects of substitution are complicated,and different replacements sometimes cause significantly *** analyze the effects of B8 replacement by different amino acids,three new insulin/single-chaininsulin mutants with BSGly replaced by Ser,Thr or Leu were prepared by protein engineering,and both theirfoldability and activity were *** general,replacement of BSGly by other amino acids causes significantdetriment to the foldability of single-chain insulin:the conformations of the three B8 mutants are essentiallydifferent from that of wild-type molecules as revealed by circular dichroism;their disulfide stabilities inredox buffer are significantly decreased:their in vitro refolding efficiencies are decreased approximatelytwo folds;the structural stabilities of the mutants with Ser or Thr substitution are decreased significantly,while Leu substitution has little effect as measured by equilibrium guanidine *** far as biologicalactivity is *** replacement of B8Gly has only a moderate effect:its insulin receptor-bindingactivity is 23% of native *** Thr or Leu replacement produces significant detriment:the receptor-binding potencies of the two mutants are less than 0.2% of native *** present results suggest thatGly is likely the only applicable natural amino acid for the B8 position of insulin where both foldability andactivity are concerned.
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