TY - JOUR
T1 - Two polyketide-synthase-associated acyltransferases are required for sulfolipid biosynthesis in Mycobacterium tuberculosis
AU - Bhatt, Kiranmai
AU - Gurcha, Sudagar S.
AU - Bhatt, Apoorva
AU - Besra, Gurdyal S.
AU - Jacobs, William R.
PY - 2007/2
Y1 - 2007/2
N2 - The methyl-branched fatty acyl components of sulfolipid-I (SL-I), a major glycolipid of the human pathogen Mycobacterium tuberculosis, are synthesized by the polyketide synthase Pks2. Rv3824c (papA1), located downstream of pks2, encodes a protein that belongs to a subfamily of acyltransferases associated with mycobacterial polyketide synthases [polyketide synthase-associated proteins (PAPs)]. The presence of a conserved acyltransferase motif (HX3DX14Y) suggested a role for PapA1 in acylation of sulfated trehalose to form SL-I. Targeted deletion of the H37Rv papA1 resulted in loss of SL-I, demonstrating its role in mycobacterial sulfolipid biosynthesis. Furthermore, SL-I synthesis was restored in the mutant strain following complementation with papA1, but not with mutant alleles of papA 1 containing alterations of key residues in the acyltransferase motif, confirming that PapA1 was an acyltransferase. While other M. tuberculosis pks clusters are associated with a single PAP-encoding gene, it was demonstrated that another open reading frame, Rv3820c (papA2), located 5.8 kb downstream of papA1 is also an acyltransferase gene involved in SLA biosynthesis: deletion of papA2 abolished SL-1 production. The absence of any partially acylated intermediates in either null mutant indicated that both PapA1 and PapA2 were required for all acylation steps of SLA assembly.
AB - The methyl-branched fatty acyl components of sulfolipid-I (SL-I), a major glycolipid of the human pathogen Mycobacterium tuberculosis, are synthesized by the polyketide synthase Pks2. Rv3824c (papA1), located downstream of pks2, encodes a protein that belongs to a subfamily of acyltransferases associated with mycobacterial polyketide synthases [polyketide synthase-associated proteins (PAPs)]. The presence of a conserved acyltransferase motif (HX3DX14Y) suggested a role for PapA1 in acylation of sulfated trehalose to form SL-I. Targeted deletion of the H37Rv papA1 resulted in loss of SL-I, demonstrating its role in mycobacterial sulfolipid biosynthesis. Furthermore, SL-I synthesis was restored in the mutant strain following complementation with papA1, but not with mutant alleles of papA 1 containing alterations of key residues in the acyltransferase motif, confirming that PapA1 was an acyltransferase. While other M. tuberculosis pks clusters are associated with a single PAP-encoding gene, it was demonstrated that another open reading frame, Rv3820c (papA2), located 5.8 kb downstream of papA1 is also an acyltransferase gene involved in SLA biosynthesis: deletion of papA2 abolished SL-1 production. The absence of any partially acylated intermediates in either null mutant indicated that both PapA1 and PapA2 were required for all acylation steps of SLA assembly.
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U2 - 10.1099/mic.0.2006/003103-0
DO - 10.1099/mic.0.2006/003103-0
M3 - Article
C2 - 17259623
AN - SCOPUS:33847218318
SN - 1350-0872
VL - 153
SP - 513
EP - 520
JO - Microbiology
JF - Microbiology
IS - 2
ER -