[Primary structure of the basic nuclear protein from spermatozoa of the mollusk Illex argentinus and its comparison with the structure of sperm proteins in other animals].

The spermatic protein of chromatin I2 of squid Illex argentinus was separated by HPLC into two components I2-1 and I2-2. Amino acid sequences of the major portion of protein I2-1 (52 residues) and the N-terminal sequence of protein I2-2 (21 residues) were determined. Arginines in protein I2-1 are arranged in clusters typical of protamines; the first cluster is in the N-terminus, the longest heterogeneous basic cluster is in the central part of the protein chain, the C-terminal part of the molecule contains two clusters of three hydroxyamino acids each.

[Primary structure of the OSCP-protein, conferring the oligomycin sensitivity to the H+-ATPase complex. II. Hydrolysis of OSCP with proteinase from Staphylococcus aureus and reconstruction of the polypeptide chain].

Hydrolysis of OSCP of bovine heart mitochondria by proteinase from Staphylococcus aureus V8 was followed by isolation of all individual peptides by means of gel-filtration and HPLC. Structural analysis of the peptides allowed to arrange BrCN-fragments and to reconstruct the complete amino acid sequence of the protein. Comparative structural analysis revealed existence of a certain homology between OSCP and delta- and b-subunits of the E.

Detailed structural analysis of exposed domains of membrane-bound Na+,K+-ATPase. A model of transmembrane arrangement.

Exposed regions of the alpha- and beta-subunits of membrane-bound Na+,K+-ATPase were in turn hydrolyzed with trypsin. Resistance of the beta-subunit to proteolysis was shown to be due mainly to the presence of disulfide bridge(s) in the molecule. A model for the spatial organisation of the enzyme in the membrane was proposed on the basis of detailed structural analysis of extramembrane regions of both subunits.

[A method of selective isolation of tryptophan- and cysteine-containing peptides by covalent chromatography. Analysis of the topography of the Na+,K+-ATPase alpha-subunit].

A procedure for highly selective isolation of tryptophan- and cysteine-containing peptides from protein hydrolysates has been developed on the basis of covalent chromatography. It includes incorporation of a thiol group into the tryptophan residues by sequential treatment of peptides with 2-nitrophenylsulfenyl chloride and beta-mercaptoethanol followed by immobilization on the corresponding supports via thiol-disulfide exchange. The technique is applicable to the analysis of the hydrolysate of the Na+, K+-ATPase alpha-subunit obtained by limited trypsinolysis of the membrane-bound enzyme.