Physiology of sialic acid capsular polysaccharide synthesis in serogroup B Neisseria meningitidis.
J Bacteriol
; 154(2): 728-36, 1983 May.
Article
en En
| MEDLINE
| ID: mdl-6302082
The pathway for biosynthesis of sialic acid capsular polysaccharide was examined in Neisseria meningitidis serogroup B strain M986 and in strain PRM102, an isogenic mutant defective in polysaccharide production. Strain PRM102 was found to possess only 25% of the level of sialyltransferase activity that was found in strain M986, but it had wild-type levels of both the N-acetylneuraminic acid (NANA) condensing enzyme and the CMP-NANA synthetase. A new meningococcal enzyme, a CMP-NANA hydrolase, was found in both meningococcal strains. This enzyme generated CMP and NANA from CMP-NANA, had a Km of 0.88 microM, had a Vmax of 10.75 nmol of NANA produced per h per mg of protein, and was completely inhibited by 45.3 microM CMP. The sialyltransferase, which also had CMP-NANA as substrate, was insensitive to CMP addition. Subcellular fractionation and purification of cytoplasmic and outer membranes on sucrose density gradients revealed that both the sialyltransferase and the CMP-NANA hydrolase were cytoplasmic membrane associated. The NANA condensing enzyme and the CMP-NANA synthetase were found to be cytosolic. A working hypothesis for the regulation of sialic acid polysaccharide synthesis was developed. The CMP-NANA hydrolase with its high affinity for CMP-NANA regulates polysaccharide formation by the sialyltransferase, whereas CMP, a product of both the sialyltransferase and the CMP-NANA hydrolase, modulates the activity of the hydrolase on the cytoplasmic membrane.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Polisacáridos Bacterianos
/
Ácidos Siálicos
/
Sialiltransferasas
/
Transferasas
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Hidrolasas Diéster Fosfóricas
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Neisseria meningitidis
Idioma:
En
Revista:
J Bacteriol
Año:
1983
Tipo del documento:
Article
Pais de publicación:
Estados Unidos