Alconada A, Flores A I, Blanco L, Cuezva J M
Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Cientificas-Universidad Autónoma de Madrid (C.S.I.C.-U.A.M.), Spain.
J Biol Chem. 1994 May 6;269(18):13670-9.
Antibodies raised against two synthetic peptides from rat liver F1-ATPase alpha-subunit sequence recognized two main heat-shock proteins from Drosophila (p71 and p56) and rat liver (p74 and p54) cells. One of the antisera showed a 20-fold higher reactivity toward Escherichia coli GroEL chaperonin than toward the alpha-subunit purified from Drosophila. Indirect immunofluorescence microscopy and subcellular fractionation experiments located both mammalian heat-shock proteins in the mitochondria. The recent findings of functional homology between chaperonins and alpha-subunits, together with the unsuspected immunological reactivity of two mitochondrial molecular chaperones toward antisera derived from two different sequence motifs of the alpha-subunit, strongly argue in favor of the existence of an evolutionary relationship between chaperonins and alpha-subunits. The complete sequence alignment of F-type ATPase alpha-subunits and chaperonins revealed the existence of eleven most conserved regions (approximately 30% of each protein sequence) with an overall amino acid identity of 20 +/- 2% and similarity of 39 +/- 4%. A search of protein data bases with three different consensus sequences derived from this alignment identified a significant proportion of proteins belonging only to these two protein families. Since the alpha-subunit protein family is evolutionary related to the other catalytic (A and beta) and regulatory (B) subunits of V- and F-type ATPases, the homology reported herein allowed us to analyze, in the chaperonin sequences, the conservation of critical residues involved in nucleotide binding. These data support the hypothesis that chaperonins and the major subunits of V- and F-type ATPases are evolutionary related.
针对大鼠肝脏F1 - ATP酶α亚基序列的两种合成肽产生的抗体，识别出果蝇（p71和p56）和大鼠肝脏（p74和p54）细胞中的两种主要热休克蛋白。其中一种抗血清对大肠杆菌GroEL伴侣蛋白的反应性比对从果蝇中纯化的α亚基高20倍。间接免疫荧光显微镜和亚细胞分级分离实验表明，这两种哺乳动物热休克蛋白都存在于线粒体中。伴侣蛋白和α亚基之间功能同源性的最新发现，以及两种线粒体分子伴侣对源自α亚基两个不同序列基序的抗血清具有意外的免疫反应性，有力地支持了伴侣蛋白和α亚基之间存在进化关系的观点。F型ATP酶α亚基和伴侣蛋白的完整序列比对揭示了存在11个最保守的区域（约占每个蛋白质序列的30%），总体氨基酸同一性为20±2%，相似性为39±4%。用从该比对中得出的三种不同共有序列搜索蛋白质数据库，发现相当一部分蛋白质仅属于这两个蛋白质家族。由于α亚基蛋白家族与V型和F型ATP酶的其他催化（A和β）亚基及调节（B）亚基在进化上相关，本文报道的同源性使我们能够在伴侣蛋白序列中分析参与核苷酸结合的关键残基的保守性。这些数据支持了伴侣蛋白与V型和F型ATP酶的主要亚基在进化上相关的假说。
