Claverie-Martin F, Diaz-Torres M R, Kushner S R
Department of Genetics, University of Georgia, Athens 30602.
Gene. 1987;54(2-3):185-95. doi: 10.1016/0378-1119(87)90486-0.
The ptr gene of Escherichia coli encodes protease III (Mr 110,000) and a 50-kDa polypeptide, both of which are found in the periplasmic space. The gene is physically located between the recC and recB loci on the E. coli chromosome. The nucleotide sequence of a 1167-bp EcoRV-ClaI fragment of chromosomal DNA containing the promoter region and 885 bp of the ptr coding sequence has been determined. S1 nuclease mapping analysis showed that the major 5' end of the ptr mRNA was localized 127 bp upstream from the ATG start codon. The open reading frame (ORF), preceded by a Shine-Dalgarno sequence, extends to the end of the sequenced DNA. Downstream from the -35 and -10 regions is a sequence that strongly fits the consensus sequence of known nitrogen-regulated promoters. A signal peptide of 23 amino acids residues is present at the N terminus of the derived amino acid sequence. The cleavage site as well as the ORF were confirmed by sequencing the N terminus of mature protease III.
大肠杆菌的ptr基因编码蛋白酶III（分子量110,000）和一种50 kDa的多肽，二者均存在于周质空间。该基因在物理位置上位于大肠杆菌染色体的recC和recB基因座之间。已确定了包含启动子区域和ptr编码序列885 bp的1167 bp染色体DNA的EcoRV-ClaI片段的核苷酸序列。S1核酸酶图谱分析表明，ptr mRNA的主要5'端位于ATG起始密码子上游127 bp处。由Shine-Dalgarno序列引导的开放阅读框（ORF）延伸至测序DNA的末端。在-35和-10区域下游是一个与已知氮调节启动子的共有序列高度匹配的序列。在推导的氨基酸序列的N末端存在一个由23个氨基酸残基组成的信号肽。通过对成熟蛋白酶III的N末端进行测序，证实了切割位点以及开放阅读框。
