[The heat shock protein of alpha-crystallin type from mycoplasma (Acholeplasma laidlawii)].

A considerable increase in several heat shock proteins (HSPs) amount in Acholeplasma laidlawii cells has been revealed after temperature rising of liquid culture; and the quantity of small HSP, named p17, was increased in a hundred of times. The p17 protein was isolated and identified as HSP of alpha-crystallin type (alpha-HSP). It became possible as a result of sequencing of 15 amino acids from N-terminal of the p17 polypeptide chain, followed by revealing of a corresponding open reading frame (ORF) in a completely sequenced genome of A. laidlawii PG 8A. Computer-based search for homologous ORFs in all 17 genomes of Mycoplasmataceae family (the mycoplasmas themselves) that had been completely sequenced to date, gives negative result. But among the representatives of Mollicutes (mycoplasma) class, the genes coding alpha-HSPs were found in two Phytoplasma species (Phytoplasmataceae family) and the acholeplasma examined (Acholeplasmataceae family). It supposed that presence or absence of alpha-HSPs in microorganisms might be connected with the fact that representatives of Acholeplasmataceae and Phytoplasmataceae families inhabit principally in plant tissues in contrast to majority of Mycoplasmataceae family, that inhabit animal and human tissues, i. e. use ecological niches with relatively constant temperature.