TY - JOUR
T1 - Discovery of a cardiolipin synthase utilizing phosphatidylethanolamine and phosphatidylglycerol as substrates
AU - Tan, Brandon K.
AU - Bogdanov, Mikhail
AU - Zhao, Jinshi
AU - Dowhan, William
AU - Raetz, Christian R.H.
AU - Guan, Ziqiang
PY - 2012/10/9
Y1 - 2012/10/9
N2 - Depending on growth phase and culture conditions, cardiolipin (CL) makes up 5-15% of the phospholipids in Escherichia coli with the remainder being primarily phosphatidylethanolamine (PE) and phosphatidylglycerol (PG). In E. coli, the cls and ybhO genes (renamed clsA and clsB, respectively) each encode a CL synthase (Cls) that catalyzes the condensation of two PG molecules to form CL and glycerol. However, a ΔclsAB mutant still makes CL in the stationary phase, indicating the existence of additional Cls. We identified a third Cls encoded by ymdC (renamed clsC ). ClsC has sequence homology with ClsA and ClsB, which all belong to the phospholipase D superfamily. The ΔclsABC mutant lacks detectible CL regardless of growth phase or growth conditions. CL can be restored to near wild-type levels in stationary phase in the triple mutant by expressing either clsA or clsB . Expression of clsC alone resulted in a low level of CL in the stationary phase, which increased to near wild-type levels by coexpression of its neighboring gene, ymdB. CL synthesis by all Cls is increased with increasing medium osmolarity during logarithmic growth and in stationary phase. However, only ClsA contributes detectible levels of CL at low osmolarity during logarithmic growth. Mutation of the putative catalytic motif of ClsC prevents CL formation. Unlike eukaryotic Cls (that use PG and CDP-diacylglycerol as substrates) or ClsA, the combined YmdB-ClsC used PE as the phosphatidyl donor to PG to form CL, which demonstrates a third and unique mode for CL synthesis.
AB - Depending on growth phase and culture conditions, cardiolipin (CL) makes up 5-15% of the phospholipids in Escherichia coli with the remainder being primarily phosphatidylethanolamine (PE) and phosphatidylglycerol (PG). In E. coli, the cls and ybhO genes (renamed clsA and clsB, respectively) each encode a CL synthase (Cls) that catalyzes the condensation of two PG molecules to form CL and glycerol. However, a ΔclsAB mutant still makes CL in the stationary phase, indicating the existence of additional Cls. We identified a third Cls encoded by ymdC (renamed clsC ). ClsC has sequence homology with ClsA and ClsB, which all belong to the phospholipase D superfamily. The ΔclsABC mutant lacks detectible CL regardless of growth phase or growth conditions. CL can be restored to near wild-type levels in stationary phase in the triple mutant by expressing either clsA or clsB . Expression of clsC alone resulted in a low level of CL in the stationary phase, which increased to near wild-type levels by coexpression of its neighboring gene, ymdB. CL synthesis by all Cls is increased with increasing medium osmolarity during logarithmic growth and in stationary phase. However, only ClsA contributes detectible levels of CL at low osmolarity during logarithmic growth. Mutation of the putative catalytic motif of ClsC prevents CL formation. Unlike eukaryotic Cls (that use PG and CDP-diacylglycerol as substrates) or ClsA, the combined YmdB-ClsC used PE as the phosphatidyl donor to PG to form CL, which demonstrates a third and unique mode for CL synthesis.
KW - Bacteria
KW - Cardiolipin-deficient
KW - Mass spectrometry
UR - http://www.scopus.com/inward/record.url?scp=84867362614&partnerID=8YFLogxK
U2 - 10.1073/pnas.1212797109
DO - 10.1073/pnas.1212797109
M3 - Article
C2 - 22988102
AN - SCOPUS:84867362614
SN - 0027-8424
VL - 109
SP - 16504
EP - 16509
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 41
ER -