TABLE 4.

Summary of transposon mutants of M. smegmatis and M. tuberculosis

ClassMutantOrganismAffected gene(s)aM. tuberculosis homolog (%)bConserved domain(s)c (E value)dPutative functiongCell morphology
Peptidoglycan biosynthesis or assemblyPM1068 M. tuberculosis ponA2 (Rv3682)PASTAe (10−6), transglycosylase (10−49), transpeptidase (10−11)HMW PBP (known)Normal
PM1081 M. smegmatis dapB dapB (84) (Rv2773c)Dihydropicolinate reductase (10−64)DAP biosynthesis (known)Normal
PM1083 M. smegmatis mtxA Rv2258c (69) O-Methyltransferase (10−4)SAM-dependent methyl- transferaseElongated, swollen termini
pbpX Rv2257c (69)β-Lactamase (10−18)fPBP involved in PG assembly
ump* Rv2256c (83)NoneUnknown
Cell divisionPM1079 M. smegmatis cdpC Rv2927c (59)DivIVA, cell division initiation protein (10−18)Cell division initiationFilamentous
nabA* Rv2926c (71)Predicted metal-binding, nucleic acid- binding protein (10−26)Regulator
PM1082 M. smegmatis cdpAB Rv1024/Rv1025 (57/76)DivIC, septum formation initiator (10−10)Cell division initiationElongated
Cell envelope processesPM1066 M. tuberculosis mmpS3 (Rv2198c)NoneUnknownNormal
PM1067 M. tuberculosis Rv2844 NoneUnknownNormal
PM1078 M. smegmatis sdrA Rv2509 (78)Short-chain dehydrogenase (10−66)Fatty acid metabolism (?)Normal
PM1084 M. smegmatis expA Rv2224c/Rv2223c (81/68)α/β hydrolase fold (10−13), acyltransferase (10−6)Exported proteaseElongated, swollen termini
  • a Genes marked with an asterisk indicate genes disrupted by transposon insertion within a given operon.

  • b Values in parentheses are percentages of identity to the M. tuberculosis gene.

  • c Determined by searching the Conserved Domain Database (33) at the National Center for Biotechnology Information website (http://www.ncbi.nlm.nih.gov/Structure/cdd/wrpsb.cgi ).

  • d E values are the probability that the domain would be found in the given translated gene by chance alone.

  • e PASTA, PBP and serine/threonine kinase-associated domain. This domain binds the β-lactam stem and acts as a d-alanyl-d-alanine sensor.

  • f Includes distantly related d,d-carboxypeptidases.

  • g HMW, high-molecular-weight; SAM, S-adenosylmethionine; PG, peptidoglycan.