Structural characterization of the protein cce_0567 from Cyanothece 51142, a metalloprotein associated with nitrogen fixation in the DUF683 family.
Structural characterization of the protein cce_0567 from Cyanothece 51142, a metalloprotein associated with nitrogen fixation in the DUF683 family.
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DOI：
10.1016/j.bbapap.2009.01.002
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发表时间：
2009-04
期刊：
影响因子：
--
通讯作者：
Addlagatta A
中科院分区：
文献类型：
--
作者：
Buchko GW;Robinson H;Addlagatta A
许多蓝细菌的基因组含有一个小蛋白的序列，该蛋白具有一个共同的“未知功能结构域”，被归类为DUF 683蛋白家族。虽然DUF 683的生物学功能尚不清楚，但它们在固氮簇中的基因组位置表明DUF 683蛋白可能在该过程中发挥作用。昼夜蓝细菌蓝杆藻属PCC 51142含有属于DUF 683家族的蛋白质的基因cce_0567（78 aa，9.0 kDa），该蛋白质为福尔斯。为了阐明DUF 683蛋白在固氮中可能发挥的生物化学作用，我们已经确定了该家族中蛋白质cce_0567的第一个晶体结构，分辨率为1.84 nm。Cce_0567在空间群P21中结晶，每个不对称单元具有两个蛋白质分子和一个Ni 2+阳离子。该蛋白由两个α-螺旋组成，残基P11至G41（α1）和L49-E74（α2），第二个α-螺旋含有一个短的310-螺旋（Y 46-N48）。螺旋之间的四残基接头（L42-D45）允许它们形成反平行束并朝向它们的末端彼此交叉。在溶液中，两个cce_0567分子可能通过约1/2蛋白质的堆积相互作用形成棒状二聚体。组氨酸-36在所有已知的DUF 683蛋白中高度保守，并且二聚体中每个分子的H36侧链的N2氮与晶体结构中的Ni 2+配位。将二价阳离子Ni 2+滴定到15 N标记的cce_0567中，仅在晶体结构中观察到的Ni 2+结合位点处或附近的1H-15 N HSQC光谱中观察到化学位移扰动。没有证据表明结合Ni 2+后cce_0567的尺寸增加，即使在大摩尔过量的Ni 2+中，表明金属不是二聚体形成所必需的。圆二色性光谱表明cce_0567是极其稳健的，具有约62 °C的熔融温度，其是可逆的。
The genomes of many cyanobacteria contain the sequence for a small protein with a common “Domain of Unknown Function” grouped into the DUF683 protein family. While the biological function of DUF683 is still not known, their genomic location within nitrogen fixation clusters suggests that DUF683 proteins may play a role in the process. The diurnal cyanobacterium Cyanothece sp. PCC 51142 contains a gene for a protein that falls into the DUF683 family, cce_0567 (78 aa, 9.0 kDa). In an effort to elucidate the biochemical role DUF683 proteins may play in nitrogen fixation, we have determined the first crystal structure for a protein in this family, cce_0567, to 1.84 Å resolution. Cce_0567 crystallized in space group P21 with two protein molecules and one Ni2+ cation per asymmetric unit. The protein is composed of two α-helices, residues P11 to G41 (α1) and L49–E74 (α2), with the second α-helix containing a short 310-helix (Y46–N48). A four-residue linker (L42–D45) between the helices allows them to form an anti-parallel bundle and cross over each other towards their termini. In solution it is likely that two molecules of cce_0567 form a rod-like dimer by the stacking interactions of ~1/2 of the protein. Histidine-36 is highly conserved in all known DUF683 proteins and the N2 nitrogen of the H36 side chain of each molecule in the dimer is coordinated with Ni2+ in the crystal structure. The divalent cation Ni2+ was titrated into 15N-labeled cce_0567 and chemical shift perturbations were observed only in the 1H–15N HSQC spectra for residues at, or near, the site of Ni2+ binding observed in the crystal structure. There was no evidence for an increase in the size of cce_0567 upon binding Ni2+, even in large molar excess of Ni2+, indicating that a metal was not required for dimer formation. Circular dichroism spectroscopy indicated that cce_0567 was extremely robust, with a melting temperature of ~62 °C that was reversible.
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影响因子：
0.9
作者：
Buchko, Garry W.;Sofia, Heidi J.
通讯作者：
Sofia, Heidi J.
DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
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通讯作者：
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作者：
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作者：
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通讯作者：
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影响因子：
2.9
作者：
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通讯作者：
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