The variant ‘his‐box’ of the C18‐Δ9‐PUFA‐specific elongase IgASE1 from Isochrysis galbana is essential for optimum enzyme activity

FEBS Letters

Fraser, Thomas C.M.¹  Qi, Baoxiu¹  Shaw, Elisabeth M.¹  Stobart, A.Keith¹  Bleakley, Claire L.¹  Lazarus, Colin M.¹ 

[1]School of Biological Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UK

关键词: Fatty acid elongating activity;    Site-directed mutagenesis;    Specificity;    Isochrysis galbana;    PUFA;    polyunsaturated fatty acid;    AA;    arachidonic acid;    EPA;    eicosapentaenoic acid;    DHA;    docosahexaenoic acid;    LA;    linoleic acid;    ALA;    α-linolenic acid;    GLA;    γ-linolenic acid;    STA;    stearidonic acid;    EDA;    ω6-eicosadienoic acid;    EtrA;    ω3-eicosatrienoic acid;   

DOI  :  10.1016/S0014-5793(03)00676-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

IgASE1, a C18-Δ9-polyunsaturated fatty acid-specific fatty acid elongase component from Isochrysis galbana, contains a variant histidine box (his-box) with glutamine replacing the first histidine of the conserved histidine-rich motif present in all other known equivalent proteins. The importance of glutamine and other variant amino acid residues in the his-box of IgASE1 was determined by site-directed mutagenesis. Results showed that all the variation in amino acid sequence between this motif in IgASE1 and the consensus sequences of other elongase components was required for optimum enzyme activity. The substrate specificity was shown to be unaffected by these changes suggesting that components of the his-box are not directly responsible for substrate specificity.

【 授权许可】

Unknown