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This review summarizes the main achievements of recent years in molecular organization research of yeast cell surface, i.e., the compartment that consists of the coordinately functioning plasma membrane, periplasmic space, and cell wall. There are data on vesicular transport to the external environment through the cell wall and the formation of channels in the wall, which indicate the possibility of dynamic rearrangements of the molecular structure of the yeast cell wall. There is an idea about the mosaic arrangement of the compartments of the plasma membrane. The hypothesis has been suggested on the heterogeneity of the molecular structure of the cell wall, which is usually considered as uniform except for the budding zones. The groups of proteins that form the molecular assembly of the yeast cell surface have been described. Special attention has been paid for proteins with amyloid properties, including Bgl2p glucanosyltransglycosylase, which is important for virulence in pathogenic yeast, and Gas1p, the first of the studied proteins of the cell surface, which is involved in the regulation of ribosomal DNA transcriptional silencing. The data on the structure of receptors localized on the cell surface and the "moonlight" proteins, involved in the cell stress response of yeasts, have been given.

Export and accumulation of various forms of invertase (EC 3.2.1.26) in the cell wall and culture liquid of the yeast Candida utilis was investigated. It was found that the high-molecular-weight CW-form of invertase is present in the cell wall. This form is not exported into the culture liquid, and it is by a third more glycosylated than the previously described exported S-form. It was shown that one of the two liquid forms of invertase exported into the culture-the glycosylated S-form--is retained in the cell wall, while the other one--the nonglycosylated F-form--was not detected in the cell wall. Based on these results, as well as data on the distribution dynamics of the enzyme in the culture liquid and in the cell wall during different growth stages of a yeast culture, we suggested that the nonglycosylated form was exported into the culture liquid via the zone of abnormal cell wall permeability and the glycosylated forms of this enzyme (both exported and nonexported) did not use this pathway (the degree of N-glycosylation is an important factor determining the final localization of the enzyme).

A homogeneous serine proteinase PC has been isolated from the Camchatka crab (Paralithodes camtschatica) hepatopancreas using affinity chromatography on arginine-Sepharose, protamine tryptic peptide-agarose and ion-exchange chromatography on Mono-Q, with a 68% yield. The enzyme is completely inhibited by diisopropylfluorophosphate, a typical inhibitor for serine proteinases. The molecular mass of the proteinase is 29 kDa, pI is 3.0. The proteinase splits Glp-Phe-Ala-pNA optimally at pH 7.5 and 47-55 degrees C; Km is 0.83 mM, kcat is 67 s-1. The enzyme is stable at pH 4-9. Proteinase PC possesses a broad substrate specificity and splits the peptide bonds formed by the carboxyl group of hydrophobic amino acids, arginine and lysine, in peptides and proteins. The enzyme hydrolyzes fibrin and collagen. Its N-terminal sequence, IVGGQEATP, reveals a 90% homology with analogous sequences of collagenolytic proteinases from other crab species.

Southern-analysis of genomic DNAs from 14 yeast species (Ascomycetes and Basidiomycetes) with alpha 1(1) chicken collagen cDNA coding for triple-helical domain as a probe, has shown that presence of genomic fragment, homologous to collagen genes of higher eucaryotes, is characteristic for yeasts. In bacterial genomes such fragments are revealed quite rarely. No collagen-like sequences has been found in known yeast proteins by computer-analysis.

The cultural broth of Bacillus brevis, strain 5/4, is capable of lysing the cell walls of Rhodotorula rubra, Candida utilis and other yeasts. The lytic action of the cultural broth is ascribed to proteolysis.