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Wednesday 3 October 2012

New thermophilic NHase sequence

I have the NCBI database set up to send me a weekly email digest of newly uploaded nitrile hydratase sequences. One of the ones which appeared this week is from the proteome of Mycobacterium hassiacum DSM 44199. This organism is one of the Mycobacterium which use humanity as its primary habitat, and this particular one was isolated from a urine sample collected in Germany in 1995. The literature reports that this organism is comfortable with temperatures up to 65 degrees C, and can deal with up to 5% salt, all of which might well offer typical "moderately thermophilic" properties to its nitrile hydratase. The alpha chain shows a "CTLCSC" sequence suggesting it is cobalt-centred, and BLASTing this sequence shows that 7 other Mycobacterium species are between 89-85% sequence similar, with non-Mycobacterium sequences being significantly different (starting below 55% similar). Interestingly most of the other Mycobacteria which are sources of these sequences are from environmental samples with much lower temperature ranges. I cant find any reference to a paper where a Mycobacterium has been exploited for its nitrile hydratase activity either in the Prasad and Bhalla review from 2010 or from a Google Scholar search. Perhaps here's one to start with.