The structure, function and properties of sirohaem decarboxylase--an enzyme with structural homology to a transcription factor family that is part of the alternative haem biosynthesis pathway.
The structure, function and properties of sirohaem decarboxylase--an enzyme with structural homology to a transcription factor family that is part of the alternative haem biosynthesis pathway.
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DOI：
10.1111/mmi.12656
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发表时间：
2014-07
影响因子：
3.6
通讯作者：
Warren MJ
中科院分区：
文献类型：
--
作者：
Palmer DJ;Schroeder S;Lawrence AD;Deery E;Lobo SA;Saraiva LM;McLean KJ;Munro AW;Ferguson SJ;Pickersgill RW;Brown DG;Warren MJ
一些细菌和古细菌通过替代途径合成血红素，这涉及将sirohaem作为代谢中间体而不是辅基进行螯合。沿着该途径，连接至C12和C18的两个乙酸侧链被西罗血红素脱羧酶（sirohaem decarboxylase）脱羧，得到二脱羧西罗血红素，所述西罗血红素脱羧酶是由AhbA和AhbB组成的异二聚体酶。进一步的修饰催化的两个相关的自由基SAM酶，AhbC和AhbD，双脱羧sirohaem转化为铁粪卟啉III和血红素分别。报道了sirohaem脱羧酶的分子特征。已经产生了脱硫脱硫弧菌、普通脱硫弧菌和巴氏甲烷八叠球菌AhbA/B的重组版本，并比较了它们的物理性质。地方vulgaris和M.巴氏酶复合物都与血红素共纯化，血红素的氧化还原状态影响血红素的活性。测定了D.对脱硫酶进行了测定，并对酶进行了结晶和结构鉴定。该酶的拓扑结构揭示了它与AsnC/Lrp家族的转录因子具有结构相似性。在两个亚基之间的空腔中形成活性位点，并获得了AhbA/B产物与二脱羧血红素的复合物。动力学稳定的羧基基团的脱羧的机制提出。
Some bacteria and archaea synthesize haem by an alternative pathway, which involves the sequestration of sirohaem as a metabolic intermediate rather than as a prosthetic group. Along this pathway the two acetic acid side-chains attached to C12 and C18 are decarboxylated by sirohaem decarboxylase, a heterodimeric enzyme composed of AhbA and AhbB, to give didecarboxysirohaem. Further modifications catalysed by two related radical SAM enzymes, AhbC and AhbD, transform didecarboxysirohaem into Fe-coproporphyrin III and haem respectively. The characterization of sirohaem decarboxylase is reported in molecular detail. Recombinant versions of Desulfovibrio desulfuricans, Desulfovibrio vulgaris and Methanosarcina barkeri AhbA/B have been produced and their physical properties compared. The D. vulgaris and M. barkeri enzyme complexes both copurify with haem, whose redox state influences the activity of the latter. The kinetic parameters of the D. desulfuricans enzyme have been determined, the enzyme crystallized and its structure has been elucidated. The topology of the enzyme reveals that it shares a structural similarity to the AsnC/Lrp family of transcription factors. The active site is formed in the cavity between the two subunits and a AhbA/B-product complex with didecarboxysirohaem has been obtained. A mechanism for the decarboxylation of the kinetically stable carboxyl groups is proposed.
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DOI：
10.1073/pnas.0809838105
发表时间：
2008-11-11
影响因子：
11.1
作者：
Lewis, Charles A., Jr.;Wolfenden, Richard
通讯作者：
Wolfenden, Richard
影响因子：
11.4
作者：
Schubert, HL;Raux, E;Warren, MJ
通讯作者：
Warren, MJ
影响因子：
6.8
作者：
Chipman, DM;Shaanan, B
通讯作者：
Shaanan, B
DOI：
10.1107/s0907444909052925
发表时间：
2010-02
期刊：
Acta crystallographica. Section D, Biological crystallography
影响因子：
--
作者：
Adams PD;Afonine PV;Bunkóczi G;Chen VB;Davis IW;Echols N;Headd JJ;Hung LW;Kapral GJ;Grosse-Kunstleve RW;McCoy AJ;Moriarty NW;Oeffner R;Read RJ;Richardson DC;Richardson JS;Terwilliger TC;Zwart PH
通讯作者：
Zwart PH
影响因子：
3.2
作者：
Jeong, Ji-A;Baek, Eun-Young;Oha, Jeong-Il
通讯作者：
Oha, Jeong-Il