Micromonospora viridifaciens

Watson JN, Newstead S, Narine AA, Taylor G, Bennet AJ (2005) Two nucleophilic mutants of the Micromonospora viridifaciens sialidase operate with retention of configuration by two different mechanisms. Chembiochem 6 1999-2004... 

J. N. Watson, S. Newstead, V. Dookhun, G. Taylor, and A. J. Bennet, Contribution of the active site aspartic acid to catalysis in the bacterial neuraminidase from Micromonospora viridifaciens, FEES Lett., 577 (2004) 265-269. 

Very remarkably, site-directed mutagenesis of the supposedly nucleophilic tyrosine of the GH 33 sialidase from Micromonospora viridifaciens yields enzymes which still work, and some of them act with inversion, rather than retention. A detailed examination of the inverting Y 370G mutant revealed that the hole left by removal of the tyrosine side-chain was now filled with water molecules surprisingly, the effect of removing the nucleophilic tyrosine... 

Evidence for a horizontal sialidase gene transfer between bacteria has been obtained by comparison of the similarities of bacterial sialidases so far sequenced [246,660,768,799]. It was found that some of the sialidases are related in accordance with the phylogenetic distances of their producers, e.g. Micromonospora viridifaciens and Actinomyces viscosus... 

The crystal structures of two representative small sialidases, with molecular weights around 40 kDa, have been determined one from Salmonella typhimurium [17] and one from Micromonospora viridifaciens [I8j. These reveal the same P-propeller fold seen in the influenza virus neuraminidase (Figure 2), despite having no sequence similarity to the viral enzyme, and not containing any disulphide bonds in contrast to the seven conserved disulfides in the viral enzyme. 

Clostridium septicum Clostridium sordellii Micromonospora viridifaciens Salmonella typhimurium Vibrio cholerae... 

Micromonospora viridifaciens Actinomyces viscosus Clostridium septicum Clostridium perfringens ("large") Clostridium perfringens ("small") Clostridium sordellii Salmonella typhimurium... 

Aisaka, K., Igarashi, A., and Uwajima, T., 1991, Purification, crystallization, and characterization of neuraminidase from Micromonospora viridifaciens, Agric. Biol. Chem. 55 997-1004. 

Sakurada, K., Ohta, T., and Hasegawa, M., 1992, Cloning, expression, and characterization of the Micromonospora viridifaciens neuraminidase gene in Streptomyces lividans, J. Bacteriol. 174 6896-6903. 

Taylor, G., Dineley, L., Glowka, M., and Laver, G., 1992b, Crystallization and preliminary crystallographic study of neuraminidase from Micromonospora viridifaciens, J. Mol. Biol. 225 1135-1136. 

---