Cytochrome b561 protein family: expanding roles and versatile transmembrane electron transfer abilities as predicted by a new classification system and protein sequence motif analyses.
Cytochrome b561 protein family: expanding roles and versatile transmembrane electron transfer abilities as predicted by a new classification system and protein sequence motif analyses.
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DOI：
10.1016/j.bbapap.2005.08.015
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发表时间：
2005-12
期刊：
影响因子：
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通讯作者：
M. Tsubaki;F. Takeuchi;N. Nakanishi
中科院分区：
文献类型：
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作者：
M. Tsubaki;F. Takeuchi;N. Nakanishi
细胞色素b561家族的特征是存在“b561核心结构域”，该结构域形成一个跨膜四螺旋束，包含四个完全保守的His残基，可能与两个血红素B基团配位。我们进行了BLAST和PSI-BLAST搜索，以获得对该蛋白质家族的结构和功能的见解。利用CLUSTAL W对来自不同生物体的b561序列进行分析，结果表明，根据特征基序，成员可分为7个亚科：A组（动物/神经内分泌）、B组（植物）、C组（昆虫）、D组（真菌）、E组（动物/TSF）、F组（植物+DoH）和G组（SDR 2）。在A组中，基序1为{FN（X）HP（X）2 M（X）2G（X）5G（X）ALLVYR}，基序2为{YSLHSW（X）G}。这两个基序在B组中也是保守的。C组和D组无显著特征。在E组中发现了基序1的一个高度保守的修饰形式{LFSWHP（X）2 M（X）3F（X）3 M（X）EAIL（X）SP（X）2SS}。基序3 {DP（X）WFY（L）H（X）3Q}和基序4 {K（X）R（X）YWN（X）YHH（X）2G（R/Y）}在F组中与基序1和2的区域不同。发现多巴胺β-羟化酶NH 2-末端区域共有的“DoH”结构域与F组和G组中的b561核心结构域形成融合蛋白。基于这些结果，我们提出了一个假设，细胞色素b561的7个亚家族的结构和功能。
Cytochrome b561 family was characterized by the presence of “b561 core domain” that forms a transmembrane four helix bundle containing four totally conserved His residues, which might coordinate two heme b groups. We conducted BLAST and PSI-BLAST searches to obtain insights on structure and functions of this protein family. Analyses with CLUSTAL W on b561 sequences from various organisms showed that the members could be classified into 7 subfamilies based on characteristic motifs; groups A (animals/neuroendocrine), B (plants), C (insects), D (fungi), E (animals/TSF), F (plants+DoH), and G (SDR2). In group A, both motif 1, {FN(X)HP(X)2M(X)2G(X)5G(X)ALLVYR}, and motif 2, {YSLHSW(X)G}, were identified. These two motifs were also conserved in group B. There was no significant features characteristic to groups C and D. A modified version of motif 1, {LFSWHP(X)2M(X)3F(X)3M(X)EAIL(X)SP(X)2SS}, was found in group E with a high degree of conservation. Both motif 3, {DP(X)WFY(L)H(X)3Q}, and motif 4, {K(X)R(X)YWN(X)YHH(X)2G(R/Y)} ,were found in group F at different regions from those of motifs 1 and 2. The “DoH” domain common to the NH2-terminal region of dopamine β-hydroxylase was found to form fusion proteins with the b561 core domains in groups F and G. Based on these results, we proposed a hypothesis regarding structures and functions of the 7 subfamilies of cytochrome b561.