Complete Amino‐Acid Sequences of DNA‐Binding Proteins HU‐1 and HU‐2 from Escherichia coli

Abstract

The DNA-binding protein HU from Escherichia coli is a heterodimer constituted of two polypeptide chains termed HU-1 and HU-2, of 90 residues each. Their primary structures were established from structural data obtained from tryptic peptides of each monomer in addition to the structural data provided by the automated Edman degradation of the dimer and by peptides derived from cleavage of the dimer with trypsin, chymotrypsin, V8 staphylococcal protease and dilute acid. The results presented in this paper confirm the amino-terminal and carboxy-terminal sequences of the dimer HU reported previously ) FEBS Lett. 89, 116-1201. The amino acid sequences of proteins HU-1 and HU-2 are identical to those of proteins NS-1 and NS-2 respectivcly, determined independently by Mende et al. [FEBS Lett. (1978) 96, 395-3981.The amino acid sequences of proteins HU-1 and HU-2 are closely related but differ by 28 residues. These proteins are characterized by their high content of hydrophobic residues represented mostly by alanine. In both proteins, half of the basic residues are scattered along the polypeptide chain and the remainder is found within two short sequences located in the carboxyterminal part of the molecule.No sequence homology could be established between the proteins HU-1 and HU-2 and any one of the five histones from different eukaryotes.

Molecular cloning, nucleotide sequence, and characterization of the Bacillus subtilis gene encoding the DNA-binding protein HBsu

“…The hbs gene is located on a 900-bp EcoRI-NdeI chromosomal fragment. In E. coli and Salmonella typhimurium, two genes were found to encode closely related proteins (HU2 and HU1) that form the heterodimeric protein HU (17,25,26,(30)(31)(32). The availability of the genes encoding HU in E. coli and S. typhimurium facilitated studies of its biological role in vivo.…”

“…The best-studied and most abundant protein is HU, present in Escherichia coli. It exists predominantly as a heterodimer (HU2 and HU1) encoded by the genes hupA and hupB (25,26,30,32). The two subunits consist of 90 amino acid residues each and have 70% identical residues.…”

Making heads or tails of the HU proteins in the planctomycete Gemmata obscuriglobus

“…Sequence analysis of the two HU proteins from G. obscuriglobus showed that the proteins contain few or no cysteine, tryptophan or tyrosine residues, which is important, since HU proteins and other nucleoid-associated proteins are known to be homologous in terms more of structure and the underlying properties of the amino acid residues rather than sequence (Laine et al, 1980;Grove & Lim, 2001;Luijsterburg et al, 2006). Other than the above-mentioned general characteristics of HU proteins, both G. obscuriglobus proteins are unlike the heterodimeric form found in enteric bacteria.…”

Primary Structure of the DNA-Binding Protein HRm from Rhizobium meliloti

“…This bond was also resistant to trypsin and a tryptic peptide which covers the sequence 60-74 was therefore obtained in the tryptic identical sequence Gly60-Arg-Asn-Pro63 of proteins HU-1 and HU-2 from Escherichiu coli, the arginyl bond was cleaved by trypsin [9]. stars indicate strictly conscrved residues and + indicates positions wherc only one change is observed when all sequenccs arc coinparcd; . '…”

“…Protein HTa condenses linear double-stranded DNA into globular particles [19]. The proteins HU-1 and HU-2 [8,9] and the protein HTa [20] have been completely sequenced. The partial sequences of the HU-type proteins from P. aeruginoscr [I I] and from the Cyanobacterium Syneclzocvstis 1211 have also been reported.…”