1lkq
From Proteopedia
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[[Image:1lkq.gif|left|200px]] | [[Image:1lkq.gif|left|200px]] | ||
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'''NMR STRUCTURE OF HUMAN INSULIN MUTANT ILE-A2-GLY, VAL-A3-GLY, HIS-B10-ASP, PRO-B28-LYS, LYS-B29-PRO, 20 STRUCTURES''' | '''NMR STRUCTURE OF HUMAN INSULIN MUTANT ILE-A2-GLY, VAL-A3-GLY, HIS-B10-ASP, PRO-B28-LYS, LYS-B29-PRO, 20 STRUCTURES''' | ||
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==About this Structure== | ==About this Structure== | ||
- | 1LKQ is a [[Protein complex]] structure | + | 1LKQ is a [[Protein complex]] structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1LKQ OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Wang, R Y.]] | [[Category: Wang, R Y.]] | ||
[[Category: Weiss, M A.]] | [[Category: Weiss, M A.]] | ||
- | [[Category: | + | [[Category: Hormone]] |
- | [[Category: | + | [[Category: Human insulin]] |
- | [[Category: | + | [[Category: Mutant]] |
- | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 00:00:56 2008'' | |
- | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + |
Revision as of 21:00, 2 May 2008
NMR STRUCTURE OF HUMAN INSULIN MUTANT ILE-A2-GLY, VAL-A3-GLY, HIS-B10-ASP, PRO-B28-LYS, LYS-B29-PRO, 20 STRUCTURES
Overview
The A and B chains of insulin combine to form native disulfide bridges without detectable isomers. The fidelity of chain combination thus recapitulates the folding of proinsulin, a precursor protein in which the two chains are tethered by a disordered connecting peptide. We have recently shown that chain combination is blocked by seemingly conservative substitutions in the C-terminal alpha-helix of the A chain. Such analogs, once formed, nevertheless retain high biological activity. By contrast, we demonstrate here that chain combination is robust to non-conservative substitutions in the N-terminal alpha-helix. Introduction of multiple glycine substitutions into the N-terminal segment of the A chain (residues A1-A5) yields analogs that are less stable than native insulin and essentially without biological activity. (1)H NMR studies of a representative analog lacking invariant side chains Ile(A2) and Val(A3) (A chain sequence GGGEQCCTSICSLYQLENYCN; substitutions are italicized and cysteines are underlined) demonstrate local unfolding of the A1-A5 segment in an otherwise native-like structure. That this and related partial folds retain efficient disulfide pairing suggests that the native N-terminal alpha-helix does not participate in the transition state of the reaction. Implications for the hierarchical folding mechanisms of proinsulin and insulin-like growth factors are discussed.
About this Structure
1LKQ is a Protein complex structure. Full crystallographic information is available from OCA.
Reference
Mechanism of insulin chain combination. Asymmetric roles of A-chain alpha-helices in disulfide pairing., Hua QX, Chu YC, Jia W, Phillips NF, Wang RY, Katsoyannis PG, Weiss MA, J Biol Chem. 2002 Nov 8;277(45):43443-53. Epub 2002 Aug 23. PMID:12196530 Page seeded by OCA on Sat May 3 00:00:56 2008
Categories: Protein complex | Chu, Y C. | Hua, Q X. | Jia, W. | Katsoyannis, P G. | Philips, N F. | Wang, R Y. | Weiss, M A. | Hormone | Human insulin | Mutant