title: Characterization of a small heat shock protein, Mx Hsp16.6, of Myxococcus xanthus.
abstract: A number of heat shock proteins in Myxococcus xanthus were previously identified by two-dimensional (2D) gel electrophoresis. One of these protein was termed Mx Hsp16.6, and the gene encoding Mx Hsp16.6 was isolated. Mx Hsp16.6 consists of 147 amino acid residues and has an estimated molecular weight of 16,642, in accordance with the apparent molecular mass in the 2D gel. An alpha-crystallin domain, typically conserved in small heat shock proteins, was found in Mx Hsp16.6. Mx Hsp16.6 was not detected during normal vegetative growth but was immediately induced after heat shock. Expression of the hsp16.6 gene was not induced by other stresses, such as starvation, oxidation, and high osmolarity. Mx Hsp16.6 was mostly localized in particles formed after heat shock and precipitated by low-speed centrifugation. Furthermore, Mx Hsp16.6 was detected in highly electron-dense particles in heat-shocked cells by immunoelectron microscopy, suggesting that it forms large complexes with heat-denatured proteins. An insertion mutation in the hsp16.6 gene resulted in lower viability during heat shock and lower acquired thermotolerance. Therefore, it is likely that Mx Hsp16.6 plays critical roles in the heat shock response in M. xanthus.
authors: Department of Biochemistry, Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ 08854-5635, USA.
authors: Mieko
authors: M
authors: Otani
authors: Toshiyuki
authors: T
authors: Ueki
authors: Satoshi
authors: S
authors: Kozuka
authors: Miki
authors: M
authors: Segawa
authors: Keiji
authors: K
authors: Sano
authors: Sumiko
authors: S
authors: Inouye
mesh_terms: D000595:Amino Acid Sequence; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006358:Hot Temperature; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016941:Myxococcus xanthus / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D038201:alpha-Crystallins
chemical_list: D006360:Heat-Shock Proteins; D038201:alpha-Crystallins