Camille Roy

Sequences of three genes specifying xylanases in Streptomyces lividans

The entire nucleotide (nt) sequences of three genes (xlnA, xlnB and xlnC) of Streptomyces lividans encoding three distinct xylanases (Xln) have been determined. The nt sequences were confirmed by comparing the deduced amino acid (aa) sequences with the ones derived from the N-terminal aa sequences of the mature purified proteins. The N-terminus of the XlnA showed some homology with either the N-termini or the C-termini of eight other Xln and of two exo-glucanases. The N-terminus of XlnB is homologous to that of XlnC and to Xln of seven other microorganisms.

The 5S RNA binding protein from yeast (Saccharomyces cerevisiae) ribosomes

The ribonucleoprotein complex between 5-S RNA and its binding protein (5-S RNA . protein complex) of yeast ribosomes was released from 60-S subunits with 25 mM EDTA and the protein component was purified by chromatography on DEAE-cellulose. This protein, designated YL3 (Mr = 36000 on dodecylsulfate gels), was relatively insoluble in neutral solutions (pH 4--9) and migrated as one of four acidic 60-S subunit proteins when analyzed by the Kaltschmidt and Wittman two-dimensional gel system. Amino acid analyses indicated lower amounts of lysine and arginine than most ribosomal proteins. Sequence homology was observed in the N terminus of YL3, and two prokaryotic 5-S RNA binding proteins, EL18 from Escherichia coli and HL13 from Halobacterium cutirubrum: Ala1-Phe2-Gln3-Lys4-Asp5-Ala6-Lys7-Ser8-Ser9-Ala10-Tyr11-Ser12-Ser13-Arg14-Phe15-Gln16-Tyr17-Pro18-Phe19-Arg20-Arg21-Arg22-Arg23-Glu24-Gly25-Lys26-Thr27-Asp28-Tyr29-Tyr35; of particular interest was homology in the cluster of basic residues (18--23). Since the protein contained one methionine residue it could be split into two fragments, CN1 (Mr = 24700) and CN2 (Mr = 11300) by CNBr treatment; the larger fragment originated from the N terminus. The N-terminal amino acid sequence of CN2 shared a limited sequence homology with an internal portion of a second 5-S RNA binding protein from E. coli, EL5, and, based also on the molecular weights of the proteins and studies on the protein binding sites in 5-S RNAs, a model for the evolution of the eukaryotic 5-S RNA binding protein is suggested in which a fusion of the prokaryotic sequences may have occurred. Unlike the native 5-S RNA . protein complex, a variety of RNAs interacted with the smaller CN2 fragment to form homogeneous ribonucleoprotein complexes; the results suggest that the CN1 fragment may confer specificity on the natural 5-S RNA-protein interaction.

Complete amino acid sequence of goose erythrocyte H5 histone and the homology between H1 and H5 histones

Summary Goose H5 histone has 193 amino acid residues and a molecular weight of 20,903. Residues 1–28 and 101–193 are probably extended while residues 29–100 are in a globular conformation. An alignment of availalbe sequences from other lysine-rich histones indicates H5 species variability is limited mostly to the N-terminal domain whereas variability between H1 and H5 proteins is within both N and C terminal domains. The constancy in size of the central domain may be important for the function of all lysine-rich histones.

A fungal cellulase shows sequence homology with the active site of hen egg-white lysozyme

The N-terminal amino acid sequence of an endo-beta-1,4-glucanase from the cellulase complex of the white-rot fungus Schizophyllum commune has been determined. The sequence from Glu-33 to Tyr-51 was homologous with the active site sequences of various hen egg-white type lysozymes, including lysozyme catalytic residues (Glu-35, Asp-52) and substrate binding residue Asn-44. The homology offers evidence for a lysozyme-type mechanism in enzymic hydrolysis of cellulose.

The primary structure of protein S10 from the small ribosomal subunit of Escherichia coli

As revealed by immuno electron microscopy studies [ 1,2] protein SlO is located on the ‘head’ of the 30 S subunit of the Escherichia coli ribosome. It can be crosslinked to proteins Sl and S3 by bifunctional reagents [3] suggesting the proteins are neighbours. Neutron scattering studies indicate [4] protein SlO is also in close probity to protein S9. Interaction between protein SlO and proteins 53 and S9 (as well as St4) has been observed during the in vitro assembly process. SlO is one of the proteins which is incorporated into the intermediate reconstitution particles at a rather late stage. Single component omission experiments indicated that protein SlO is involved in tRNA-binding to the ribosomes (reviewed in [5]). Here, we report the complete primary structure of protein SlO and present its secondary structure based on 4 prediction progr~mes. Furthermore, a comparison of the primary structure of protein SlO has been made with that of other ribosomal proteins.

Isolation and partial primary sequence of a xylanase from the yeast Cryptococcus albidus

An endo-1,4-β-xylanase (EC 3.2.1.8) was isolated from the culture medium of Cryptococcus albidus. The enzyme was glycosylated and had an apparent molecular weight of 48 000. The enzyme preparation was resolved by isoelectric focusing into two xylanase components with pI values of 5.7 and 5.3, respectively. In time course digestion the enzyme degraded xylan, producing first a mixture of xylose oligosaccharides of various lengths and mainly xylose and xylobiose as end-products. The amino acid sequence of the first 72 residues shows some homology with the regions surrounding the catalytic residues Glu-35 and Asp-52 of egg lysozyme. The homology suggests a lysozyme-type mechanism of glycosidic bond cleavage for xylanase.

Amino acid sequence homologies between H1 and H5 histones.

Abstract The amino acid sequence of the first 112 residues of goose H5 and the first 38 residues of pigeon H5 has been determined. When a gap of 12 residues is introduced in the N-terminal regions of avian H5, almost half of the residues become identical to those of H1 from various species. The region of this gap corresponds to a homologous repeating sequence in H1. This suggests a deleation or duplication in this region and that the genes for H1 and H5 histones have evolved from a common ancestral gene.

Species variability of N-terminal sequence of avian erythrocyte-specific histone H5

Abstract A comparison of the N-terminal amino acid sequence of H5 isolated from chicken, quail, duck, goose and pigeon shows considerable sequence variation. With the possible exception of the very lysine-rich histone H1, H5 variation is much more extensive than that reported previously for other histones. The observed sequence diversity is in agreement with the known taxonomic grouping of these birds.

Amino acid sequence and thermostability of xylanase A from schizophyllum commune

The amino acid sequence (197 residues) of xylanase A from the fungus, Schizophyllum commune, was determined by automated analysis of peptides from proteolytic and acid cleavage. The sequence is similar to two Trichoderma xylanases (approximately 56% identical amino acids), but also shows at least 40% identities with xylanases from Bacillus subtilis, B. pumilus and B. circulans. The conserved regions of the enzyme contain only two glutamic acid residues which implicates their possible involvement in catalysis. The disulfide bond in xylanase A is not conserved in this family. In spite of this, the B. subtilis xylanase was found to be more thermostable than xylanase A.

Homologies of the N-terminal sequences of asclepains and papain.

Sequences to residue 21 have been determined for the two asclepains, cysteinyl proteases isolated from milkweed (Asclepias syriaca L.). These were compared with the sequence for papain, and extensive homology was found.