Ramkhamhaeng University; Mahidol University; National Science & Technology Development Agency - Thailand; National Center Genetic Engineering & Biotechnology (BIOTEC)
Type
Article
Source Title
FEMS MICROBIOLOGY LETTERS
ISSN
0378-1097
Year
2008
Volume
286
Issue
2
Page
166-170
Open Access
Bronze
Publisher
OXFORD UNIV PRESS
DOI
10.1111/j.1574-6968.2008.01268.x
Format
PDF
Abstract
The 57-bp tandem repeats located in the Mycobacterium tuberculosis leuA gene code for the alpha-isopropylmalate synthase (alpha-IPMS). It is unique to this pathogen. It was previously demonstrated that the leuA-coding sequence Rv3710, containing the tandem repeats, can be translated to an active alpha-IPMS. The objective of the present study was to investigate the significance and effect of the two 57-bp tandem repeats upon gene expression and the general properties of alpha-IPMS. The putative M. tuberculosis H37Rv leuA gene with and without the tandem repeats was cloned by PCR and expressed in an Escherichia coli host. The enzyme product was studied for general properties, comparing that from a native leuA gene containing two repeats and that from the 57-bp tandem repeats deletion mutant. Upon deletion of the two 57-bp tandem repeats, the expression level of leuA from M. tuberculosis H37Rv was comparable with that of the native form. The general properties of the two types of enzymes were similar. They were both functional with the same range of optimal temperature and optimal pH for activity and with similar enzyme stability. Deletion of the repeats had no detectable effect on leuA expression level or the general properties of the enzyme product.
