Crystal structure analysis of a mutant beta-ketoacyl-[acyl carrier protein] synthase II from Streptococcus pneumoniaeCrystal structure analysis of a mutant beta-ketoacyl-[acyl carrier protein] synthase II from Streptococcus pneumoniae

Structural highlights

2alm is a 1 chain structure with sequence from Streptococcus pneumoniae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 2.6Å
Ligands:
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

Q9FBC2_STREE Catalyzes the condensation reaction of fatty acid synthesis by the addition to an acyl acceptor of two carbons from malonyl-ACP.[PIRNR:PIRNR000447]

Evolutionary Conservation

 

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

beta-Ketoacyl-ACP synthases catalyze the condensation steps in fatty acid and polyketide synthesis and are targets for the development of novel antibiotics and anti-obesity and anti-cancer agents. The roles of the active site residues in Streptococcus pneumoniae FabF (beta-ketoacyl-ACP synthase II; SpFabF) were investigated to clarify the mechanism for this enzyme superfamily. The nucleophilic cysteine of the active site triad was required for acyl-enzyme formation and the overall condensation activity. The two active site histidines in the elongation condensing enzyme have different electronic states and functions. His337 is essential for condensation activity, and its protonated Nepsilon stabilizes the negative charge developed on the malonyl thioester carbonyl in the transition state. The Nepsilon of His303 accelerated catalysis by deprotonating a structured active site water for nucleophilic attack on the C3 of malonate, releasing bicarbonate. Lys332 controls the electronic state of His303 and also plays a critical role in the positioning of His337. Phe396 functions as a gatekeeper that controls the order of substrate addition. These data assign specific roles for each active site residue and lead to a revised general mechanism for this important class of enzymes.

Roles of the active site water, histidine 303, and phenylalanine 396 in the catalytic mechanism of the elongation condensing enzyme of Streptococcus pneumoniae.,Zhang YM, Hurlbert J, White SW, Rock CO J Biol Chem. 2006 Jun 23;281(25):17390-9. Epub 2006 Apr 16. PMID:16618705[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

See Also

References

  1. Zhang YM, Hurlbert J, White SW, Rock CO. Roles of the active site water, histidine 303, and phenylalanine 396 in the catalytic mechanism of the elongation condensing enzyme of Streptococcus pneumoniae. J Biol Chem. 2006 Jun 23;281(25):17390-9. Epub 2006 Apr 16. PMID:16618705 doi:10.1074/jbc.M513199200

2alm, resolution 2.60Å

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