Biochemical and structural characterization of a novel family of cystathionine β-synthase domain proteins fused to a Zn ribbon-like domain
Biochemical and structural characterization of a novel family of cystathionine β-synthase domain proteins fused to a Zn ribbon-like domain
复制标题
DOI：
10.1016/j.jmb.2007.10.060
复制
发表时间：
2008-01-04
影响因子：
5.6
通讯作者：
Yakunin, Alexander F.
中科院分区：
文献类型：
--
作者：
Proudfoot, Michael;Sanders, Stephen A.;Yakunin, Alexander F.
我们已经确定了一个新的蛋白质家族，其中N-末端胱硫醚β-合酶（CBS）结构域融合到C-末端锌带结构域。在大肠杆菌中过表达并纯化了四种蛋白：来自嗜酸热浆菌的TA 0289、来自火山热浆菌的TV 1335、来自激烈火球菌的PF 1953和来自堀越火球菌的PH 0267。纯化的蛋白质在溶液中具有红色/紫色，并且具有红蛋白多辛（Rds）的典型吸收光谱。对纯化蛋白质的金属分析揭示了几种金属的存在，其中铁和锌是最丰富的金属（2-67%的铁和12-74%的锌）。汞和铁结合的TA 0289（1.5-2.0埃分辨率）的晶体结构揭示了一个二聚体蛋白质，其亚基间的接触完全由两个胱硫醚β-合酶亚结构域的α-螺旋形成，而C-末端结构域具有经典的Zn带状平面结构。所有蛋白质都被化学还原剂（抗坏血酸或连二亚硫酸盐）或来自E.在NADH存在下，还原TA 0289。发现能够将电子从马心脏转移到细胞色素C。同样，从酿酒酵母中纯化的锌带蛋白KTI 11在溶液中具有紫色和类Rd吸收光谱，含有铁和锌，并且被来自E.杆菌因此，重组锌带结构域从古细菌和酵母菌表现出的RD样电子载体活性在体外。我们认为，在体内，一些锌带域也可能结合铁，因此具有电子载体活性，增加了另一个生理作用，这个大家庭的重要蛋白质。(c)2007爱思唯尔有限公司保留所有权利。
We have identified a novel family of proteins, in which the N-terminal cystathionine beta-synthase (CBS) domain is fused to the C-terminal Zn ribbon domain. Four proteins were overexpressed in Escherichia coli and purified: TA0289 from Thermoplasma acidophilum, TV1335 from Thermoplasma volcanium, PF1953 from Pyrococcus furiosus, and PH0267 from Pyrococcus horikoshii. The purified proteins had a red/purple color in solution and an absorption spectrum typical of rubredoxins (Rds). Metal analysis of purified proteins revealed the presence of several metals, with iron and zinc being the most abundant metals (2-67% of iron and 12-74% of zinc). Crystal structures of both mercury- and iron-bound TA0289 (1.5-2.0 angstrom resolution) revealed a dimeric protein whose intersubunit contacts are formed exclusively by the alpha-helices of two cystathionine beta-synthase subdomains, whereas the C-terminal domain has a classical Zn ribbon planar architecture. All proteins were reversibly reduced by chemical reductants (ascorbate or dithionite) or by the general Rd reductase NorW from E. coli in the presence of NADH. Reduced TA0289. was found to be capable of transferring electrons to cytochrome C from horse heart. Likewise, the purified Zn ribbon protein KTI11 from Saccharomyces cerevisiae had a purple color in solution and an Rd-like absorption spectrum, contained both iron and zinc, and was reduced by the Rd reductase NorW from E. coli. Thus, recombinant Zn ribbon domains from archaea and yeast demonstrate an Rd-like electron carrier activity in vitro. We suggest that, in vivo, some Zn ribbon domains might also bind iron and therefore possess an electron carrier activity, adding another physiological role to this large family of important proteins. (c) 2007 Elsevier Ltd. All rights reserved.