| Autor: |
Whittingham, Jean L., Zhang Youshang, Žáková, Lenka, Dodson, Eleanor J., Turkenburg, Johan P., Brange, Jens, Dodson, G. Guy |
| Předmět: |
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| Zdroj: |
Acta Crystallographica: Section D (Wiley-Blackwell); May2006, Vol. 62 Issue 5, p505-511, 7p, 6 Diagrams, 1 Chart |
| Abstrakt: |
Despentapeptide (des-B26-B30) insulin (DPI), an active modified insulin, has been crystallized in the presence of 20% acetic acid pH 2. A crystal structure analysis to 1.8 Å spacing (space group I222) revealed that the DPI molecule, which is unable to make β-strand interactions for physiological dimer formation and is apparently monomeric in solution, formed an alternative lattice-generated dimer. The formation of this dimer involved interactions between surfaces which included the B9–B19 α-helices (usually buried by the dimer–dimer contacts within the native hexamer). The two crystallographically independent molecules within the dimer were essentially identical and were similar in conformation to T-state insulin as seen in the T6 insulin hexamer. An unusual feature of each molecule in the dimer was the presence of two independent conformations at the B-chain C-terminus (residues B20–B25). Both conformations were different from that of native insulin, involving a 3.5 Å displacement of the B20–B23 β-turn and a repositioning of residue PheB25 such that it made close van der Waals contact with the main body of the molecule, appearing to stabilize the B-chain C-terminus. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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