Chai Ai Fen, Johnston Jodie M, Bunker Richard D, Bulloch Esther M M, Evans Genevieve L, Lott J Shaun, Baker Edward N
Structural Biology Laboratory, School of Biological Sciences and Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
Acta Crystallogr Sect F Struct Biol Cryst Commun. 2013 Dec;69(Pt 12):1354-6. doi: 10.1107/S1744309113027000. Epub 2013 Nov 28.
In Mycobacterium tuberculosis, the protein MbtN (Rv1346) catalyzes the formation of a double bond in the fatty-acyl moiety of the siderophore mycobactin, which is used by this organism to acquire essential iron. MbtN is homologous to acyl-CoA dehydrogenases, whose general role is to catalyze the α,β-dehydrogenation of fatty-acyl-CoA conjugates. Mycobactins, however, contain a long unsaturated fatty-acid chain with an unusual cis double bond conjugated to the carbonyl group of the mycobactin core. To characterize the role of MbtN in the dehydrogenation of this fatty-acyl moiety, the enzyme has been expressed, purified and crystallized. The crystals diffracted to 2.3 Å resolution at a synchrotron source and were found to belong to the hexagonal space group H32, with unit-cell parameters a = b = 139.10, c = 253.09 Å, α = β = 90, γ = 120°.
在结核分枝杆菌中，蛋白质MbtN（Rv1346）催化铁载体分枝杆菌酸的脂肪酰基部分中双键的形成，该生物体利用分枝杆菌酸获取必需的铁。MbtN与酰基辅酶A脱氢酶同源，其一般作用是催化脂肪酰基辅酶A共轭物的α，β-脱氢。然而，分枝杆菌酸含有一条长的不饱和脂肪酸链，其具有与分枝杆菌酸核心羰基共轭的不寻常顺式双键。为了表征MbtN在该脂肪酰基部分脱氢中的作用，该酶已被表达、纯化并结晶。这些晶体在同步加速器源处衍射至2.3 Å分辨率，发现属于六方空间群H32，晶胞参数a = b = 139.10，c = 253.09 Å，α = β = 90，γ = 120°。
