Evidence linking the Pseudomonas oleovorans alkane ω‐hydroxylase, an integral membrane diiron enzyme, and the fatty acid desaturase family

FEBS Letters

Whittle, Edward¹  Shanklin, John¹ 

[1] Department of Biology, Brookhaven National Laboratory, Building 463, 50 Bell Ave., Upton, NY 11973, USA

关键词: Alkane ω-hydroxylase;    Oxygenase;    EC 1.14.15.3;    Desaturase;    Cytochrome P450;    AlkB;    alkane ω-hydroxylase;    PCR;    polymerase chain reaction;   

DOI  :  10.1016/S0014-5793(03)00529-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Pseudomonas oleovorans alkane ω-hydroxylase (AlkB) is an integral membrane diiron enzyme that shares a requirement for iron and oxygen for activity in a manner similar to that of the non-heme integral membrane desaturases, epoxidases, acetylenases, conjugases, ketolases, decarbonylase and methyl oxidases. No overall sequence similarity is detected between AlkB and these desaturase-like enzymes by computer algorithms; however, they do contain a series of histidine residues in a similar relative positioning with respect to hydrophobic regions thought to be transmembrane domains. To test whether these conserved histidine residues are functionally equivalent to those of the desaturase-like enzymes we used scanning alanine mutagenesis to test if they are essential for activity of AlkB. These experiments show that alanine substitution of any of the eight conserved histidines results in complete inactivation, whereas replacement of three non-conserved histidines in close proximity to the conserved residues, results in only partial inactivation. These data provide the first experimental support for the hypotheses: (i) that the histidine motif in AlkB is equivalent to that in the desaturase-like enzymes and (ii) that the conserved histidine residues play a vital role such as coordinating the Fe ions comprising the diiron active site.

【 授权许可】

Unknown