4l77: Difference between revisions

<StructureSection load='4l77' size='340' side='right' caption='[[4l77]], [[Resolution|resolution]] 1.38&Aring;' scene=''>

<table><tr><td colspan='2'>[[4l77]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Atcc_51113 Atcc 51113]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4L77 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4L77 FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CNL:1,3,3-TRIMETHYL-2-OXABICYCLO[2.2.2]OCTANE'>CNL</scene>, <scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene>, <scene name='pdbligand=PEG:DI(HYDROXYETHYL)ETHER'>PEG</scene>, <scene name='pdbligand=PG4:TETRAETHYLENE+GLYCOL'>PG4</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr>

<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">CIN A, cinA ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=57706 ATCC 51113])</td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4l77 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4l77 OCA], [http://pdbe.org/4l77 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=4l77 RCSB], [http://www.ebi.ac.uk/pdbsum/4l77 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=4l77 ProSAT]</span></td></tr>

[[http://www.uniprot.org/uniprot/CINA_CITBR CINA_CITBR]] Involved in the degradation of cineol (eucalyptol). Catalyzes the initial hydroxylation of cineole exclusively at the pro-R carbon to give the (S)-6beta-hydroxycineole. Cineole is the natural substrate of CinA.

In P450cin, Tyr81, Asp241, Asn242, two water molecules, and the substrate participate in a complex H-bonded network. The role of this H-bonded network in substrate binding and catalysis has been probed by crystallography, spectroscopy, kinetics, isothermal titration calorimetry (ITC), and molecular dynamics. For the Y81F mutant, the substrate binds about 20-fold more weakly and Vmax decreases by about 30% in comparison to WT. The enhanced susceptibility of the heme to H2O2-mediated destruction in Y81F suggests that this mutant favors the open, low-spin conformational state. Asn242 H-bonds directly with the substrate, and replacing this residue with Ala results in water taking the place of the missing Asn side chain. This mutant exhibits a 70% decrease in activity. Crystal structures and molecular dynamics simulations of substrate-bound complexes show that the solvent has more ready access to the active site, especially for the N242A mutant. This accounts for about a 64% uncoupling of electron transfer from substrate hydroxylation. These data indicate the importance of the interconnected water network on substrate binding and on the open/closed conformational equilibrium, which are both critically important for maintaining high-coupling efficiency.

 

== References ==

[[Category: Atcc 51113]]

[[Category: Madrona, Y]]

[[Category: Poulos, T L]]

[[Category: Cindoxin]]

[[Category: P450]]