1dxc
From Proteopedia
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'''CO COMPLEX OF MYOGLOBIN MB-YQR AT 100K''' | '''CO COMPLEX OF MYOGLOBIN MB-YQR AT 100K''' | ||
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[[Category: Travaglini-Allocatelli, C.]] | [[Category: Travaglini-Allocatelli, C.]] | ||
[[Category: Vallone, B.]] | [[Category: Vallone, B.]] | ||
| - | [[Category: | + | [[Category: Co complex]] |
| - | [[Category: | + | [[Category: Oxygen storage]] |
| - | [[Category: | + | [[Category: Respiratory protein]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 14:23:33 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 11:23, 2 May 2008
CO COMPLEX OF MYOGLOBIN MB-YQR AT 100K
Overview
We determined the structure of the photolytic intermediate of a sperm whale myoglobin (Mb) mutant called Mb-YQR [Leu-(B10)-->Tyr; His(E7)-->Gln; Thr(E10)-->Arg] to 1.4-A resolution by ultra-low temperature (20 K) x-ray diffraction. Starting with the CO complex, illumination leads to photolysis of the Fe-CO bond, and migration of the photolyzed carbon monoxide (CO*) to a niche in the protein 8.1 A from the heme iron; this cavity corresponds to that hosting an atom of Xe when the crystal is equilibrated with xenon gas at 7 atmospheres [Tilton, R. F., Jr., Kuntz, I. D. & Petsko, G. A. (1984) Biochemistry 23, 2849-2857]. The site occupied by CO* corresponds to that predicted by molecular dynamics simulations previously carried out to account for the NO geminate rebinding of Mb-YQR observed in laser photolysis experiments at room temperature. This secondary docking site differs from the primary docking site identified by previous crystallographic studies on the photolyzed intermediate of wild-type sperm whale Mb performed at cryogenic temperatures [Teng et al. (1994) Nat. Struct. Biol. 1, 701-705] and room temperature [Srajer et al. (1996) Science 274, 1726-1729]. Our experiment shows that the pathway of a small molecule in its trajectory through a protein may be modified by site-directed mutagenesis, and that migration within the protein matrix to the active site involves a limited number of pre-existing cavities identified in the interior space of the protein.
About this Structure
1DXC is a Single protein structure of sequence from Physeter catodon. Full crystallographic information is available from OCA.
Reference
The role of cavities in protein dynamics: crystal structure of a photolytic intermediate of a mutant myoglobin., Brunori M, Vallone B, Cutruzzola F, Travaglini-Allocatelli C, Berendzen J, Chu K, Sweet RM, Schlichting I, Proc Natl Acad Sci U S A. 2000 Feb 29;97(5):2058-63. PMID:10681426 Page seeded by OCA on Fri May 2 14:23:33 2008
