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| - | [[Image:1w8p.gif|left|200px]] | + | {{Seed}} |
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| | {{STRUCTURE_1w8p| PDB=1w8p | SCENE= }} | | {{STRUCTURE_1w8p| PDB=1w8p | SCENE= }} |
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| - | '''STRUCTURAL PROPERTIES OF THE B25TYR-NME-B26PHE INSULIN MUTANT.'''
| + | ===STRUCTURAL PROPERTIES OF THE B25TYR-NME-B26PHE INSULIN MUTANT.=== |
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| - | ==Overview==
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| - | The origins of differentiation of insulin from insulin-like growth factor I (IGF-I) are still unknown. To address the problem of a structural and biological switch from the mostly metabolic hormonal activity of insulin to the predominant growth factor activities of IGF-I, an insulin analogue with IGF-I-like structural features has been synthesized. Insulin residues Phe(B25) and Tyr(B26) have been swapped with the IGF-I-like Tyr(24) and Phe(25) sequence with a simultaneous methylation of the peptide nitrogen of residue Phe(B26). These modifications were expected to introduce a substantial kink in the main chain, as observed at residue Phe(25) in the IGF-I crystal structure. These alterations should provide insight into the structural origins of insulin-IGF-I structural and functional divergence. The [Tyr(B25)NMePhe(B26)] mutant has been characterized, and its crystal structure has been determined. Surprisingly, all of these changes are well accommodated within an insulin R6 hexamer. Only one molecule of each dimer in the hexamer responds to the structural alterations, the other remaining very similar to wild-type insulin. All alterations, modest in their scale, cumulate in the C-terminal part of the B-chain (residues B23-B30), which moves toward the core of the insulin molecule and is associated with a significant shift of the A1 helix toward the C-terminus of the B-chain. These changes do not produce the expected bend of the main chain, but the fold of the mutant does reflect some structural characteristics of IGF-1, and in addition establishes the CO(A19)-NH(B25) hydrogen bond, which is normally characteristic of T-state insulin. | + | The line below this paragraph, {{ABSTRACT_PUBMED_15610023}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 15610023 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_15610023}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Mutant]] | | [[Category: Mutant]] |
| | [[Category: X-ray structure]] | | [[Category: X-ray structure]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 13:18:41 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 15:10:04 2008'' |
Revision as of 12:10, 29 July 2008
Template:STRUCTURE 1w8p
STRUCTURAL PROPERTIES OF THE B25TYR-NME-B26PHE INSULIN MUTANT.
Template:ABSTRACT PUBMED 15610023
About this Structure
1W8P is a Protein complex structure of sequences from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Toward the insulin-IGF-I intermediate structures: functional and structural properties of the [TyrB25NMePheB26] insulin mutant., Zakova L, Brynda J, Au-Alvarez O, Dodson EJ, Dodson GG, Whittingham JL, Brzozowski AM, Biochemistry. 2004 Dec 28;43(51):16293-300. PMID:15610023
Page seeded by OCA on Tue Jul 29 15:10:04 2008
