The N-acetylmuramic acid 6-phosphate etherase gene promotes growth and cell differentiation of cyanobacteria under light-limiting conditions.
Inactivation of sll0861 in Synechocystis sp. strain PCC 6803 or the homologous gene alr2432 in Anabaena sp. strain PCC 7120 had no effect on the growth of these organisms at a light intensity of 30 micromol photons m(-2) s(-1) but reduced their growth at a light intensity of 5 or 10 micromol photons m(-2) s(-1). In Anabaena, inactivation of the gene also significantly reduced the rate of heterocyst differentiation under low-light conditions. The predicted products of sll0861 and alr2432 and homologs of these genes showed similarity to N-acetylmuramic acid 6-phosphate etherase (MurQ), an enzyme involved in peptidoglycan recycling, in Escherichia coli. E. coli murQ and the cyanobacterial homologs could functionally substitute for each other. We hypothesize that murQ in cyanobacteria promotes low-light adaptation through reutilization of peptidoglycan degradation products.
Jiang
Haibo
H
Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, People's Republic of China.
Kong
Renqiu
R
Xu
Xudong
X
D017033:Anabaena / Q000166:cytology / Q000201:enzymology / Q000235:genetics / Q000528:radiation effects; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D000458:Cyanobacteria / Q000166:cytology / Q000201:enzymology* / Q000235:genetics / Q000528:radiation effects*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000235:genetics / Q000378:metabolism; D008027:Light; D008954:Models, Biological; D046939:Synechocystis / Q000166:cytology / Q000201:enzymology / Q000235:genetics / Q000528:radiation effects
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D006026:Glycoside Hydrolases; C504247:MurQ protein, E coli