Primary structure of histone H2B from gonads of the starfish Asterias rubens

Abstract

The complete amino acid sequence (121 residues) of histone H2B from gonads of the starfish Asterias rubens has been established from structural data obtained essentially from large fragments generated by cleavage of histone H2B at aspartyl residues and by limited hydrolysis of the dimer H2A-H2B with mouse submaxillary gland protease.No real sequence homology can be found between the amino-terminal sequence (residues 1-21) of starfish and calf H2B. One non-conservative substitution (serine-32 in calf + lysine-28 in starfish) leads to the presence of a cluster of eight basic residues (sequence 23 -30) and to the disappearance of a potential site of phosphorylation.A particular structural feature of starfish histone H2B is the presence of N-dimethylproline at its aminoterminal end. By comparison with N-terminal acetylation, which is commonly found in histones, N-terminal methylation is rarely observed. At the present time the functional significance of the N-terminal methylation as well as that of the proline-rich nature of the amino-terminal sequence of the starfish histone H2B remain to be defined.The amino acid sequences of core particle histones were first determined for calf thymus, then in a variety of tissues and species [l] [21] and found to be located in the N-terminal region.The peculiar structural characteristics and the higher degree of variability observed in histone H2B from Echinidae [I] have led us to investigate the primary structure of histone H2B in Asterinidae, another family of the phylum echinoderms.In this paper we report the complete amino acid sequence of histone H2B from gonads of the starfish Asterias rubens. This sequence was established from structural data provided by tryptic peptides and large fragments derived from cleavage of the protein at aspartic acid and arginine residues.Starfish histone H2B is devoid of a free amino-terminal group. The blocking group has been identified as dimethylproline. The amino-terminal blocking of histones by methylation has only been observed previously in Tetrahymena histone H2B [22]. MATERIALS AND METHODS MaterialsMature starfish were obtained from the Station Marine, Wimereux (France). After excision, gonads were frozen in solid C 0 2 and kept at -20" C until use.Trypsin (treated with TosPheCH2C1) and carboxypeptidases A and B (treated with PhMeS0,F) were obtained from Worthington. Thermolysin was from Merck. Arg-C endoproteinase from mouse submaxillaris gland was purchased from Boehringer.Dimethylallylamine, propan-1 -01, dithioerythritol and anhydrous hydrazine were sequanal grade from Pierce. Benzene and chloro-1 -butane for sequential analysis were purchased from SDS (Peypin, France). Phenylisothiocyanate, heptane and heptafluorobutyric acid were sequanal grade from Merck. Polybrene was purchased from Aldrich and the dipeptide GlyGly from Sigma. All other reagents were of the highest purity available.Isolation of histone H2B and of histone dimer H2A-H2BChromatin was isolated from gonads as described in [23]. The crude fraction F2b was extracted...

Mapping of Lysine Methylation and Acetylation in Core Histones of Neurospora crassa

“…We also observed y 4 , y 5 , y 6 +Ac ions, providing evidence for acetylation of K7. Similar methylation of an N-terminal proline has been observed in H2B from Drosophila melanogaster (30) and from gonads of the starfish Asterias rubens (31). Along this line, N-terminal alanine methylation was found for Tetrahymena histone H2B (32) and Arabidopsis histone H2B variants HTB-9 and HTB-11 (33).…”

Analysis of the Arabidopsis Cytosolic Ribosome Proteome Provides Detailed Insights into Its Components and Their Post-translational Modification

“…Interestingly L12 is the only Arabidopsis cytosolic ribosomal protein predicted to have the ProPro-Lys-N-terminal sequence after methionine removal, and this sequence is conserved in almost every eukaryotic L12 protein sequence available. At the time of this publication, we could find in the literature relatively few reported examples of proteins modified by N-terminal proline methylation: the histone H2B from the starfish Asterias rubens that was confirmed by NMR to have an N,N-dimethylproline structure at its N terminus (43), the orthologous histone H2B of Drosophila (44), the cytochrome c 557 of the protozoan Crithidia oncopelti (45,46), and the cytosolic ribosomal protein S25 of S. cerevisiae (47). Remarkably all of these proteins were shown to have the same Pro-Pro-Lys-N-terminal structure as we have shown here for ribosomal protein L12 in Arabidopsis.…”

Identification of erythro‐β‐hydroxyasparagine in the EGF‐like domain of human C1r

“…Such a peak is usually interpreted as a pseudo-molecular peak corresponding to a protonated (MH+) or cationised (MNa+) form of the peptide. It could also be interpreted as a molecular ion if the peptide is already ionised [16]. As shown in table 2, these different hypotheses lead to the following molecular masses for peptide CNlaTWT9 TL8: 1098.4, 1076.4 and 1099.4 Da.…”