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1bon
From Proteopedia
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THREE-DIMENSIONAL STRUCTURE OF BOMBYXIN-II, AN INSULIN-RELATED BRAIN-SECRETORY PEPTIDE OF THE SILKMOTH BOMBYX MORI: COMPARISON WITH INSULIN AND RELAXIN
Overview
The three-dimensional solution structure of bombyxin-II, an insulin-like, two-chain peptide produced by the brain of the silkworm Bombyx mori, has, been determined by simulated annealing calculations based on 535 distance, constraints and 24 torsion-angle constraints derived from NMR data and, three distance constraints of the disulfide bonds. To our knowledge, this, is the first three-dimensional structure determined for an invertebrate, insulin-related peptide. The root-mean-square deviations between the best, 10 structures and the mean structure are 0.58(+/- 0.15) A for the backbone, heavy atoms (N, C alpha, C) and 1.03(+/- 0.18) A for all non-hydrogen atom, if less well-defined N and C termini (A1, A20, B(-2) to B4 and B23 to B25), are excluded. The overall main-chain structure of bombyxin-II is similar, to that of insulin. However, there are significant conformational and, functional differences in their B-chain C-terminal parts. The B-chain, C-terminal part of bombyxin-II adopts an extension of the B-chain central, helix like that of relaxin and is not required for bombyxin activity, while the corresponding part of insulin adopts a sharp turn and a, beta-strand and is essential for insulin activity. This structure, demonstrates that bombyxin-II is more closely related to relaxin than to, insulin, and suggests that insulin might have evolved the additional, receptor-recognition site in the B-chain C-terminal beta-strand to, distinguish itself from bombyxin and relaxin. The structure of bombyxin-II, thus provides novel insights into the receptor recognition and divergent, molecular evolution of insulin-superfamily peptides.
About this Structure
1BON is a Protein complex structure of sequences from Bombyx mori. Full crystallographic information is available from OCA.
Reference
Three-dimensional solution structure of bombyxin-II an insulin-like peptide of the silkmoth Bombyx mori: structural comparison with insulin and relaxin., Nagata K, Hatanaka H, Kohda D, Kataoka H, Nagasawa H, Isogai A, Ishizaki H, Suzuki A, Inagaki F, J Mol Biol. 1995 Nov 10;253(5):749-58. PMID:7473749
Page seeded by OCA on Tue Nov 20 11:47:45 2007
