Packer J C, André D, Howe C J
Department of Biochemistry, University of Cambridge, UK.
Plant Mol Biol. 1995 Jan;27(1):199-204. doi: 10.1007/BF00019191.
Type I signal peptidases are a widespread family of enzymes which remove the presequences from proteins translocated across cell membranes, including thylakoid and cytoplasmic membranes of cyanobacteria and thylakoid membranes of chloroplasts. We have cloned and sequenced a signal peptidase gene from the thermophilic cyanobacterium Phormidium laminosum which is believed to encode an enzyme common to both membrane systems. The deduced amino acid sequence is 203 residues long and although the overall similarity among signal peptidases is rather low there are a number of identifiable conserved regions present. The P. laminosum enzyme is predicted to have a single transmembrane domain, in contrast to other Gram-negative bacterial sequences, but similar to other type I signal peptidases.
I型信号肽酶是一类广泛存在的酶家族，可从跨细胞膜转运的蛋白质中去除前导序列，这些细胞膜包括蓝细菌的类囊体膜和细胞质膜以及叶绿体的类囊体膜。我们已经从嗜热蓝细菌层状席藻中克隆并测序了一个信号肽酶基因，该基因被认为编码一种存在于这两种膜系统中的共同酶。推导的氨基酸序列长203个残基，尽管信号肽酶之间的总体相似性相当低，但仍存在一些可识别的保守区域。与其他革兰氏阴性细菌序列不同，层状席藻的这种酶预计有一个单一的跨膜结构域，但与其他I型信号肽酶相似。
