View source for 1kmy

[[Image:1kmy.gif|left|200px]]<br /><applet load="1kmy" size="350" color="white" frame="true" align="right" spinBox="true" 
caption="1kmy, resolution 2.0&Aring;" />
'''Crystal Structure of 2,3-dihydroxybiphenyl 1,2-dioxygenase Complexed with 2,3-dihydroxybiphenyl under Anaerobic Condition'''<br />

==Overview==
The steady-state cleavage of catechols by 2,3-dihydroxybiphenyl 1, 2-dioxygenase (DHBD), the extradiol dioxygenase of the biphenyl biodegradation pathway, was investigated using a highly active, anaerobically purified preparation of enzyme. The kinetic data obtained using 2,3-dihydroxybiphenyl (DHB) fit a compulsory order ternary complex mechanism in which substrate inhibition occurs. The Km for dioxygen was 1280 +/- 70 microM, which is at least 2 orders of magnitude higher than that reported for catechol 2,3-dioxygenases. Km and Kd for DHB were 22 +/- 2 and 8 +/- 1 microM, respectively. DHBD was subject to reversible substrate inhibition and mechanism-based inactivation. In air-saturated buffer, the partition ratios of catecholic substrates substituted at C-3 were inversely related to their apparent specificity constants. Small organic molecules that stabilized DHBD most effectively also inhibited the cleavage reaction most strongly. The steady-state kinetic data and crystallographic results suggest that the stabilization and inhibition are due to specific interactions between the organic molecule and the active site of the enzyme. t-Butanol stabilized the enzyme and inhibited the cleavage of DHB in a mixed fashion, consistent with the distinct binding sites occupied by t-butanol in the crystal structures of the substrate-free form of the enzyme and the enzyme-DHB complex. In contrast, crystal structures of complexes with catechol and 3-methylcatechol revealed relationships between the binding of these smaller substrates and t-butanol that are consistent with the observed competitive inhibition.

==About this Structure==
1KMY is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Burkholderia_cepacia Burkholderia cepacia] with <scene name='pdbligand=FE2:'>FE2</scene>, <scene name='pdbligand=BPY:'>BPY</scene> and <scene name='pdbligand=TBU:'>TBU</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Biphenyl-2,3-diol_1,2-dioxygenase Biphenyl-2,3-diol 1,2-dioxygenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.13.11.39 1.13.11.39] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1KMY OCA]. 

==Reference==
Molecular basis for the stabilization and inhibition of 2, 3-dihydroxybiphenyl 1,2-dioxygenase by t-butanol., Vaillancourt FH, Han S, Fortin PD, Bolin JT, Eltis LD, J Biol Chem. 1998 Dec 25;273(52):34887-95. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=9857017 9857017]
[[Category: Biphenyl-2,3-diol 1,2-dioxygenase]]
[[Category: Burkholderia cepacia]]
[[Category: Single protein]]
[[Category: Bolin, J T.]]
[[Category: Han, S.]]
[[Category: BPY]]
[[Category: FE2]]
[[Category: TBU]]
[[Category: 2]]
[[Category: 3-dihydroxybiphenyl]]
[[Category: dioxygenase]]
[[Category: oxidoreductase]]

''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:35:50 2008''