scholarly journals Myxococcus xanthus spore coat protein S may have a similar structure to vertebrate lens βγ-crystallins

Nature ◽  
1985 ◽  
Vol 315 (6022) ◽  
pp. 771-773 ◽  
Author(s):  
Graeme Wistow ◽  
Lesley Summers ◽  
Tom Blundell
Microbiology ◽  
2011 ◽  
Vol 157 (7) ◽  
pp. 1886-1896 ◽  
Author(s):  
Xiaoyan Leng ◽  
Wei Zhu ◽  
Jing Jin ◽  
Xiaohua Mao

Many bacteria use the chaperone–usher (CU) secretion pathway to assemble on their surfaces typical or atypical fimbrial organelles. Four consecutive genes of Myxococcus xanthus DK1622, MXAN3885–3882, were predicted to constitute an operon encoding a CU-like system involved in the assembly of the spore coat; however, experimental evidence supporting this hypothesis was lacking. In this study, co-transcription of MXAN3885–3883 was verified, and we found that this operon was expressed 12–15 h after initiation of M. xanthus development under conditions of stringent starvation. The MXAN3885 protein, which is highly homologous to, but expressed earlier than, the spore coat protein U of another M. xanthus strain, DZF1, was present mainly on the outer surface of myxospores. Inactivation of MXAN3883, encoding a putative outer membrane usher, inhibited assembly of MXAN3885 protein on spore surfaces and caused certain morphological alterations in the spore coat. Hence, the CU-like pathway in M. xanthus indeed functions in spore coat biogenesis. Based on chaperone amino acid sequence comparisons, our analysis suggests that the structural basis of the M. xanthus CU-like pathway for spore coat assembly may be different from that of most surface structures assembled by classical CU systems.


2006 ◽  
Vol 188 (21) ◽  
pp. 7609-7616 ◽  
Author(s):  
Alicia Monroe ◽  
Peter Setlow

ABSTRACT The Bacillus subtilis spore coat protein GerQ is necessary for the proper localization of CwlJ, an enzyme important in the hydrolysis of the peptidoglycan cortex during spore germination. GerQ is cross-linked into high-molecular-mass complexes in the spore coat late in sporulation, and this cross-linking is largely due to a transglutaminase. This enzyme forms an ε-(γ-glutamyl) lysine isopeptide bond between a lysine donor from one protein and a glutamine acceptor from another protein. In the current work, we have identified the residues in GerQ that are essential for transglutaminase-mediated cross-linking. We show that GerQ is a lysine donor and that any one of three lysine residues near the amino terminus of the protein (K2, K4, or K5) is necessary to form cross-links with binding partners in the spore coat. This leads to the conclusion that all Tgl-dependent GerQ cross-linking takes place via these three lysine residues. However, while the presence of any of these three lysine residues is essential for GerQ cross-linking, they are not essential for the function of GerQ in CwlJ localization.


2007 ◽  
Vol 142 (6) ◽  
pp. 681-689 ◽  
Author(s):  
R. Kuwana ◽  
H. Takamatsu ◽  
K. Watabe

1982 ◽  
Vol 202 (1) ◽  
pp. 231-241 ◽  
Author(s):  
G S A B Stewart ◽  
D J Ellar

The spore-coat fraction from Bacillus megaterium KM, when prepared by extraction of lysozyme-digested integuments with SDS (sodium dodecyl sulphate) and urea, contains three N-terminal residues and a major component of apparent mol.wt. 17500. Electron microscopy of this fraction shows it to consist of an ordered multilamellar structure similar to that which forms the coat region of intact spores. The 17500-dalton protein, which has been purified to homogeneity, has an N-terminal methionine residue, has high contents of glycine, proline, cysteine and acidic amino acids and readily polymerized even in the presence of thiol-reducing agents. It is first synthesized between late Stage IV and early Stage V, which correlates with the morphological appearance of spore coat. Before Stage VI the 17500-dalton protein is extractable from sporangia by SDS in the absence of thiol-reducing reagents. Between Stage VI and release of mature spores the protein becomes resistant to extraction by SDS unless it is supplemented by a thiol-reducing reagent. In addition to that of the spore-coat protein, the timing of synthesis of all the integument proteins was analysed by SDS/polyacrylamide-gel electrophoresis and non-equilibrium pH-gradient electrophoresis. Several integument proteins are conservatively synthesized from as early as 1h after the end of exponential growth (t1), which may reflect protein incorporation into the spore outer membrane.


Sign in / Sign up

Export Citation Format

Share Document