Abstract
Malonyl-CoA:acyl carrier protein transacylase (MAT) provides acyl-ACP thioesters for the biosynthesis of aromatic polyketides, and thus is the primary gatekeeper of substrate specificity in type II PKS. A recent report described the X-ray crystal structure of the Streptomyces coelicolor MAT and suggested active site residues which may be important for substrate selectivity [Keatinge-Clay, A. T., et al. (2003) Structure 11, 147-154]. Mutants were made to test the proposed roles of these residues, and the enzymes were characterized kinetically with respect to native and non-native substrates. The activity of the MAT was observed to be greatly attenuated in many of the observed mutants; however, the Km for malonyl-CoA was only modestly affected. Our results suggest the MAT uses an active site that is rigorously ordered around the acyl-thioester moiety of the acyl-CoA to facilitate rapid and efficient transacylation to an ACP. Our results also suggest that the MAT does not discriminate against α-substituted acyl-CoA thioesters solely on the basis of substrate size.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 11057-11064 |
| Number of pages | 8 |
| Journal | Biochemistry |
| Volume | 42 |
| Issue number | 37 |
| DOIs | |
| State | Published - Sep 23 2003 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Biochemistry
Cite this
Structure-based mutagenesis of the malonyl-CoA : acyl carrier protein transacylase from Streptomyces coelicolor. / Koppisch, Andrew T; Khosla, Chaitan.
In: Biochemistry, Vol. 42, No. 37, 23.09.2003, p. 11057-11064.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Structure-based mutagenesis of the malonyl-CoA
T2 - acyl carrier protein transacylase from Streptomyces coelicolor
AU - Koppisch, Andrew T
AU - Khosla, Chaitan
PY - 2003/9/23
Y1 - 2003/9/23
N2 - Malonyl-CoA:acyl carrier protein transacylase (MAT) provides acyl-ACP thioesters for the biosynthesis of aromatic polyketides, and thus is the primary gatekeeper of substrate specificity in type II PKS. A recent report described the X-ray crystal structure of the Streptomyces coelicolor MAT and suggested active site residues which may be important for substrate selectivity [Keatinge-Clay, A. T., et al. (2003) Structure 11, 147-154]. Mutants were made to test the proposed roles of these residues, and the enzymes were characterized kinetically with respect to native and non-native substrates. The activity of the MAT was observed to be greatly attenuated in many of the observed mutants; however, the Km for malonyl-CoA was only modestly affected. Our results suggest the MAT uses an active site that is rigorously ordered around the acyl-thioester moiety of the acyl-CoA to facilitate rapid and efficient transacylation to an ACP. Our results also suggest that the MAT does not discriminate against α-substituted acyl-CoA thioesters solely on the basis of substrate size.
AB - Malonyl-CoA:acyl carrier protein transacylase (MAT) provides acyl-ACP thioesters for the biosynthesis of aromatic polyketides, and thus is the primary gatekeeper of substrate specificity in type II PKS. A recent report described the X-ray crystal structure of the Streptomyces coelicolor MAT and suggested active site residues which may be important for substrate selectivity [Keatinge-Clay, A. T., et al. (2003) Structure 11, 147-154]. Mutants were made to test the proposed roles of these residues, and the enzymes were characterized kinetically with respect to native and non-native substrates. The activity of the MAT was observed to be greatly attenuated in many of the observed mutants; however, the Km for malonyl-CoA was only modestly affected. Our results suggest the MAT uses an active site that is rigorously ordered around the acyl-thioester moiety of the acyl-CoA to facilitate rapid and efficient transacylation to an ACP. Our results also suggest that the MAT does not discriminate against α-substituted acyl-CoA thioesters solely on the basis of substrate size.
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U2 - 10.1021/bi0349672
DO - 10.1021/bi0349672
M3 - Article
VL - 42
SP - 11057
EP - 11064
JO - Biochemistry
JF - Biochemistry
SN - 0006-2960
IS - 37
ER -