New aspects of the molecular evolution of legumains, Asn-specific cysteine proteinases.

The molecular evolution of asparagine-specific cysteine proteinases, called legumains, from plants and animals was analyzed using newly available related amino acid sequences from lower eukaryotes, bacteria and Archaea. The results suggest that genuine legumains originate from prokaryote pro-legumains. The evolutionary roots of genuine legumains from plants and animals descend from Parabasalia and Alveolata before developing into their respective separate branches headed by Chlorophyta and Placozoa.

Protein dynamics and proteolysis in plant vacuoles.

Plant cells cannot live without their vacuoles. The tissues and organs of a plant contain a wide variety of differentiated and specialized vacuoles -- even a single plant cell can possess two or more types of vacuoles. Vacuolar proteins are encoded by nuclear genes and synthesized in the cytoplasm.

Seed legumains are expressed in stamens and vegetative legumains in seeds of Nicotiana tabacum L.

Detailed analysis of the expression pattern of seven legumain genes from Nicotiana tabacum L. cv. SNN revealed that it showed neither coincidences with the branches of the phylogenetic tree of legumains nor with their conventional assignment to organs.

Seed-specific promoters direct gene expression in non-seed tissue.

The organ specificity of four promoters that are known to direct seed-specific gene expression was tested. Whereas the phaseolin (phas)- and legumin B4 (leB4)-promoters were from genes encoding 7S and 11S globulins from Phaseolus vulgaris and Vicia faba, respectively, the usp- and the sbp-promoters were from non-storage protein genes of V. faba.

Crystal structures and structural stabilities of the disulfide bond-deficient soybean proglycinin mutants C12G and C88S.

The constituent subunits of seed storage protein 11S globulin have two disulfide bonds that are common among 11S globulins from legume and nonlegume seeds. In the case of the A1aB1b subunit of soybean 11S globulin, glycinin, Cys12-Cys45 and Cys88-Cys298 are observed by X-ray crystallography. The significance of these two disulfide bonds for structural stability was investigated by mutagenesis of Cys12 to Gly and of Cys88 to Ser.