Objective: To study the sequences of amino-acids and their related genes of rifampin-dependent Mycobacterium tuberculosis.
Methods: The strains of rifampin-dependent, rifampin-resistant and rifampin-sensitive Mycobacterium tuberculosis were evaluated by L-J method. The proteins of 134 strains were analyzed by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (SDS-PAGE). The sequences of amino-acids of the proteins with differential expressions were determined by Q-TOF2 liquid chromatography-electra mist spray-quadrupole -time of flight cascade mass spectrograph (LC-ESI-MS-MS, Q-TOF2). The corresponding gene codes for the proteins were analyzed.
Results: The protein SDS-PAGE profile of 41 of 49 (41/49) rifampin-dependent strains showed a high expression of a protein band (molecular weight 43,000), representative of 30%-50% of the total proteins differed from rifampin resistance and the control strains. The protein profile of H(37)Rv standard strains, 28 (28/30) rifampin-sensitive strains and 44 (44/54) rifampin-resistant strains showed no relevant high expression. The protein of high expression was identified as the hypothetical protein Rv0341 of Mycobacterium tuberculosis H(37)Rv with a molecular weight (M) of 43,894, a iso-potential point of 5.25 and a score of 183. No mutation was found in the 1,440 bp encoding sequence in various strains.
Conclusions: The hypothetical protein Rv0341 is related to the rifampin-dependent strains, so it can be regarded as an indicator for rifampin-dependent Mycobacterium tuberculosis. Rifampin upregulated the expression of Rv0341 in rifampin-dependent Mycobacterium tuberculosis. Whether the hypothetical protein Rv0341 is related to virulence and synthesis of the cell wall of Mycobacterium tuberculosis needs further study.