Heat shock proteins and antigens of Mycobacterium tuberculosis

The heat shock response of Mycobacterium tuberculosis has been characterized in detail by one- and two-dimensional polyacrylamide gel electrophoresis after metabolic labeling with [35S]methionine and 14C-amino acids. A temperature increase from 37 to 42 degrees C induced elevated synthesis of three major proteins corresponding to the DnaK, GroEL, and GroES proteins of M. tuberculosis previously identified as prominent antigens. At higher temperatures (45 to 48 degrees C), synthesis of GroEL decreased and novel heat shock proteins with molecular masses of 90, 28, 20, and 15 kDa were observed. These new proteins did not comigrate with known antigens during two-dimensional gel electrophoresis. The heat shock response is discussed with regard to the possible importance of transcriptional regulation of mycobacterial genes in vivo.