1phb: Difference between revisions

Revision as of 15:28, 21 February 2008

INHIBITOR-INDUCED CONFORMATIONAL CHANGE IN CYTOCHROME P450-CAM

OverviewOverview

The X-ray crystal structures of cytochrome P-450CAM complexed with both enantiomers of a chiral, multifunctional inhibitor have been refined to R-factors of 21.0% [(+)-enantiomer] and 19.6% [(-)-enantiomer] at approximately 2.1-A resolution. Binding of either enantiomer, both considerably larger than the natural substrate camphor, results in similar, dramatic structural changes in the enzyme. In contrast to all previous P-450CAM crystallographic structures, the Tyr96 side chain is not pointing "down" toward the heme but is rather directed "up" into the proposed substrate access channel. This conformational change is accompanied by the displacement of the Phe193 side chain out into the solvent at the enzyme surface. These changes are consistent with the assignment of this region of the enzyme as the access channel [Poulos et al. (1986) Biochemistry 25, 5314-5322] and suggest that several aromatic residues lining the channel may be involved in substrate recognition and channeling to the active site. The cation usually observed coordinated to the Tyr96 carbonyl oxygen is missing in the presence of the (+)-enantiomer but is present with the (-)-enantiomer. The Phe87 side chain, located near the inhibitor binding site, adopts different orientations depending upon which enantiomer is bound. Finally, electron density reveals that although the inhibitor enantiomers were dichlorinated as provided, when bound to P-450CAM the chlorine atoms are present at only 0-20% occupancy, probably reflecting selective binding of impurities in the samples. Coordinates of these inhibited P-450CAM complexes have been deposited in the Brookhaven Protein Data Bank [Bernstein et al. (1977) J. Mol. Biol. 112, 535-542].

About this StructureAbout this Structure

1PHB is a Single protein structure of sequence from Pseudomonas putida with and as ligands. Active as Camphor 5-monooxygenase, with EC number 1.14.15.1 Full crystallographic information is available from OCA.

ReferenceReference

Inhibitor-induced conformational change in cytochrome P-450CAM., Raag R, Li H, Jones BC, Poulos TL, Biochemistry. 1993 May 4;32(17):4571-8. PMID:8485133

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-[[Image:1phb.gif|left|200px]]<br /><applet load="1phb" size="450" color="white" frame="true" align="right" spinBox="true"
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 caption="1phb, resolution 1.6&Aring;" />
 '''INHIBITOR-INDUCED CONFORMATIONAL CHANGE IN CYTOCHROME P450-CAM'''<br />
 ==Overview==
-The X-ray crystal structures of cytochrome P-450CAM complexed with both, enantiomers of a chiral, multifunctional inhibitor have been refined to, R-factors of 21.0% [(+)-enantiomer] and 19.6% [(-)-enantiomer] at, approximately 2.1-A resolution. Binding of either enantiomer, both, considerably larger than the natural substrate camphor, results in, similar, dramatic structural changes in the enzyme. In contrast to all, previous P-450CAM crystallographic structures, the Tyr96 side chain is not, pointing "down" toward the heme but is rather directed "up" into the, proposed substrate access channel. This conformational change is, accompanied by the displacement of the Phe193 side chain out into the, solvent at the enzyme surface. These changes are consistent with the, assignment of this region of the enzyme as the access channel [Poulos et, al. (1986) Biochemistry 25, 5314-5322] and suggest that several aromatic, residues lining the channel may be involved in substrate recognition and, channeling to the active site. The cation usually observed coordinated to, the Tyr96 carbonyl oxygen is missing in the presence of the (+)-enantiomer, but is present with the (-)-enantiomer. The Phe87 side chain, located near, the inhibitor binding site, adopts different orientations depending upon, which enantiomer is bound. Finally, electron density reveals that although, the inhibitor enantiomers were dichlorinated as provided, when bound to, P-450CAM the chlorine atoms are present at only 0-20% occupancy, probably, reflecting selective binding of impurities in the samples. Coordinates of, these inhibited P-450CAM complexes have been deposited in the Brookhaven, Protein Data Bank [Bernstein et al. (1977) J. Mol. Biol. 112, 535-542].
+The X-ray crystal structures of cytochrome P-450CAM complexed with both enantiomers of a chiral, multifunctional inhibitor have been refined to R-factors of 21.0% [(+)-enantiomer] and 19.6% [(-)-enantiomer] at approximately 2.1-A resolution. Binding of either enantiomer, both considerably larger than the natural substrate camphor, results in similar, dramatic structural changes in the enzyme. In contrast to all previous P-450CAM crystallographic structures, the Tyr96 side chain is not pointing "down" toward the heme but is rather directed "up" into the proposed substrate access channel. This conformational change is accompanied by the displacement of the Phe193 side chain out into the solvent at the enzyme surface. These changes are consistent with the assignment of this region of the enzyme as the access channel [Poulos et al. (1986) Biochemistry 25, 5314-5322] and suggest that several aromatic residues lining the channel may be involved in substrate recognition and channeling to the active site. The cation usually observed coordinated to the Tyr96 carbonyl oxygen is missing in the presence of the (+)-enantiomer but is present with the (-)-enantiomer. The Phe87 side chain, located near the inhibitor binding site, adopts different orientations depending upon which enantiomer is bound. Finally, electron density reveals that although the inhibitor enantiomers were dichlorinated as provided, when bound to P-450CAM the chlorine atoms are present at only 0-20% occupancy, probably reflecting selective binding of impurities in the samples. Coordinates of these inhibited P-450CAM complexes have been deposited in the Brookhaven Protein Data Bank [Bernstein et al. (1977) J. Mol. Biol. 112, 535-542].
 ==About this Structure==
-PHB is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pseudomonas_putida Pseudomonas putida] with HEM and PFZ as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Camphor_5-monooxygenase Camphor 5-monooxygenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.14.15.1 1.14.15.1] Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1PHB OCA].
+PHB is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pseudomonas_putida Pseudomonas putida] with <scene name='pdbligand=HEM:'>HEM</scene> and <scene name='pdbligand=PFZ:'>PFZ</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Camphor_5-monooxygenase Camphor 5-monooxygenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.14.15.1 1.14.15.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1PHB OCA].
 ==Reference==
@@ Line 14: / Line 14: @@
 [[Category: Pseudomonas putida]]
 [[Category: Single protein]]
-[[Category: Poulos, T.L.]]
+[[Category: Poulos, T L.]]
 [[Category: HEM]]
 [[Category: PFZ]]
 [[Category: oxidoreductase(oxygenase)]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Nov 20 23:48:42 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:28:46 2008''