The Journal of biological chemistry
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The amino acid sequence of the histidine binding protein of Salmonella typhimurium was determined by automated sequence analysis of reduced and S-pyridylethylated histidine binding protein and fragments derived by chemical and enzymatic cleavage of the native protein. The fragments were the products of cleavage at methionine residues by cyanogen bromide, cleavage at tryptophan residues by 2-nitrophenylsulfenyl-3-methyl-3-bromo-3H-indole (BrNps-skatole), limited enzymatic digestion at arginine residues, and enzymatic digestion at Glu-X bonds by the Staphylococcus aureus V8 protease. The sequence of the COOH-terminal residues was determined using bovine carboxypeptidases A and B and amino acid analysis. The histidine binding protein was found to contain 238 amino acid residues and to have a molecular weight of 26,104 calculated from sequence.
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The amino acid sequence of the single-stranded DNA-binding protein encoded by gene 32 of bacteriophage T4 has been determined by manual and automated sequencing of peptides derived from cyanogen bromide cleavage and digestion with trypsin, chymotrypsin, and staphylococcal protease. Tryptic digestion of citraconylated or succinylated gene 32 protein yields five peptides containing 4, 27, 42, 65, and 163 residues, respectively, which can be separated by Sephadex chromatography. Each of these tryptic peptides was subjected to automated sequencing and, if necessary, more extensive cleavage. ⋯ The "A" region (residues 254 to 301) has been implicated in controlling the helix-destabilizing "activity" of gene 32 protein and in interacting with other T4 DNA replication proteins. The "A" region has a net charge of -10 and, in addition, contains two unusual stretches of 4 serine residues separated by glycine 284. The region between positions 72 and 116 contains 6 of the 8 tyrosine residues in the protein and may be important for DNA binding.