Differential spontaneous folding of mycolic acids from Mycobacterium tuberculosis

Abstract

Mycolic acids are structural components of the mycobacterial cell wall that have been implicated in thepathogenicity and drug resistance of certain mycobacterial species. They also offer potential in areassuch as rapid serodiagnosis of human and animal tuberculosis. It is increasingly recognized that con-formational behavior of mycolic acids is very important in understanding all aspects of their function.Atomistic molecular dynamics simulations, in vacuo, of stereochemically defined Mycobacterium tuber-culosis mycolic acids show that they fold spontaneously into reproducible conformational groupings.One of the three characteristic mycolate types, the keto-mycolic acids, behaves very differently fromeither -mycolic acids or methoxy-mycolic acids, suggesting a distinct biological role. However, subtleconformational behavioral differences between all the three mycolic acid types indicate that cooperativeinterplay of individual mycolic acids may be important in the biophysical properties of the mycobacterialcell envelope and therefore in pathogenicity.