Effects of mutations in Bacillus subtilis genome decreasing the protease activity on the formation of subtilisin molecular forms]

Multiple molecular forms of subtilisin--extracellular serine protease produced by the wild strain Bac. subtilis A-50 and its mutant strains with the protease activity decreased two-fold and more were studied. Six molecular forms of subtilisin were found on the whole when 33 mutant strains have been investigated under the experimental conditions. It is essential that both the wild and each of mutant strains under study produced not more than three out of these six forms. Three molecular forms of subtilisin from the mutant strains are similar to those found in the wild strain A-50, and have the molecular weight, of 27 000-30 000. Three other forms of subtilisin were revealed only in the mutant strains, and had the molecular weight of about 20 000. Apparently there is only one structural gene for subtilisin in Bac. subtilis genome. The appearence of multiple molecular forms of subtilisin may be due to the post-translational modifications (limited proteolysis) of the initial type of enzyme, i.e. pre-subtilisin. Probably, that certain mulations not affecting the structural gene can significantly change the expression of such gene by varying of the degree of product modifications.     

Inhibition of casein kinase type 2 activity by formation of complexes with mRNA in vivo

It is known that casein kinase 2 possesses, besides the protein kinase, an RNA-binding activity. Using ligand blotting it has been demonstrated that the both activities are localized on the alpha- and alpha'-subunits of the enzyme. Casein kinase 2 is suppressed in vitro by polyuridylic acid. A part of the intracellular pool of casein kinase 2 is found in the informosomes. The informosomes and free proteins were separated by centrifugation in a sucrose density gradient, and each fraction was incubated with casein and [gamma-32P]ATP. The informosome-bound protein kinase is completely inhibited, while the free protein kinases heavily phosphorylate casein. It is concluded that the activity of casein kinase 2 can be regulated by the reversible formation of complexes with RNA.     

Isolation and properties of serine proteinase from Aspergillus oryzae

A serine proteinase having an activity optimum at pH 6.7-8.2 has been isolated from amylorisine P-10x (a mixture of Aspergillus oryzae enzymes) by chromatography on DEAE-Sephadex A-50 and bacitracin Sepharose 4B. The proteinase is fully inactivated by phenylmethylsulfonylfluoride and diisopropylfluorophosphonate, the specific inhibitors of the enzyme, and has a pI at pH 7.5. The molecular mass of serine proteinase is 30000 Da; its amino acid composition appears as: Met2, Asp33, Thr18, Ser29, Glu21, Pro9, Glu32, Ala38, Val24, Ile16, Leu15, Tyr8, Phe8, His8, Lys18, Arg4, Trp6. The N-terminal sequence of the serine proteinase: Gly-Leu-Thr-Thr-Gln-Lys-Ser-Ala-Pro-Trp-Gly-Leu-Gly-Ser-Ile-Ser-Xaa-Lys- Gly-Gln-Gln-Ser-Thr-Asp-Tyr-Ile-Tyr, which coincides practically completely with the corresponding sequence of alkaline proteinase of A. oryzae, ATCC20386, has been determined. Similar to subtilisin, the enzyme catalyzes the condensation of leucine and alanine p-nitroanilides with N-benzyloxycarbonyl-alanyl-alanine and glycyl-alanine methyl esters.     

Panel of X-linked single-nucleotide polymorphic markers for DNA identification (XSNPid) based on multiplex genotyping by multilocus PCR and MALDI-TOF mass spectrometry

Human genetic markers linked with the X chromosome (X-linked) are used in the field of population and medical genetics, as well as for DNA identification of individuals in forensic science and forensic medicine. We proposed an XSNPid panel that consists of 66 unlinked single nucleotide X chromosome markers and developed a protocol for their multiplex genotyping using multilocus PCR and MALDI-TOF mass spectrometry. The XSNPid panel is genotyped within two multiplexes (36 and 30 markers). The developed protocol provides an efficient genotype reading; the fraction of determined genotypes is 98.29%. The high level of gene diversity (0.461) for the X-linked SNPs included in the panel is characteristic of the Russian population. A total of 63 out of 66 markers that provide a high efficiency of genotyping and independent inheritance are suitable for DNA identification purposes. The XSNPid panel is characterized by a very high discriminating ability when studying the Russian population. The probability of genotype coincidence in two unrelated individuals is 9 × 10^–27 for women and 2 × 10^–18 for men. Also, the XSNPid panel has a greater multiplex capacity in addition to a higher discriminating ability compared to the other closest analogues of the X chromosome SNP sets, which makes it more cost effective and less time consuming. The XSNPid panel is a convenient tool, not only for individual DNA identification, but also for population genetic studies.     

A new subtilisin-like proteinase from roots of the dandelion Taraxacum officinale Webb S. L.

A serine proteinase from roots of Taraxacum officinale Webb S. L. was isolated by affinity chromatography and gel-filtration on Superose 6R using FPLC. The enzyme is a 67-kD glycoprotein containing 54% carbohydrate which we have named taraxalisin. The substrate specificity of taraxalisin toward synthetic peptides and oxidized insulin B-chain is comparable with that of cucumisin from Cucumis melo and the subtilisin-like serine proteinase macluralisin from Maclura pomifera. The proteinase is inactivated by DFP and PMSF. Taraxalisin exhibits maximal activity at pH 8.0. The pH range for stability of the enzyme is narrow--6.0-9.0. The temperature optimum for the subtilisin-like activity is 40 degrees C. The N-terminal sequence of taraxalisin has 40% of its residues identical to those of subtilisin Carlsberg. Thus, the serine proteinase from dandelion roots is a member of the subtilisin family, which is evidently widespread in the plant kingdom.