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1f7t
From Proteopedia
| 1f7t, resolution 1.80Å () | |||||||||
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| Ligands: | , , , | ||||||||
| Activity: | [acyl-carrier-protein_synthase Holo-[acyl-carrier-protein] synthase], with EC number 2.7.8.7 | ||||||||
| Domains: | acpS | ||||||||
| Related: | 1f7l | ||||||||
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||
HOLO-(ACYL CARRIER PROTEIN) SYNTHASE AT 1.8A
BACKGROUND: Holo-(acyl carrier protein) synthase (AcpS), a member of the phosphopantetheinyl transferase superfamily, plays a crucial role in the functional activation of acyl carrier protein (ACP) in the fatty acid biosynthesis pathway. AcpS catalyzes the attachment of the 4'-phosphopantetheinyl moiety of coenzyme A (CoA) to the sidechain of a conserved serine residue on apo-ACP. RESULTS: We describe here the first crystal structure of a type II ACP from Bacillus subtilis in complex with its activator AcpS at 2.3 A. We also have determined the structures of AcpS alone (at 1.8 A) and AcpS in complex with CoA (at 1.5 A). These structures reveal that AcpS exists as a trimer. A catalytic center is located at each of the solvent-exposed interfaces between AcpS molecules. Site-directed mutagenesis studies confirm the importance of trimer formation in AcpS activity. CONCLUSIONS: The active site in AcpS is only formed when two AcpS molecules dimerize. The addition of a third molecule allows for the formation of two additional active sites and also permits a large hydrophobic surface from each molecule of AcpS to be buried in the trimer. The mutations Ile5-->Arg, Gln113-->Glu and Gln113-->Arg show that AcpS is inactive when unable to form a trimer. The co-crystal structures of AcpS-CoA and AcpS-ACP allow us to propose a catalytic mechanism for this class of 4'-phosphopantetheinyl transferases.
Crystal structures of substrate binding to Bacillus subtilis holo-(acyl carrier protein) synthase reveal a novel trimeric arrangement of molecules resulting in three active sites., Parris KD, Lin L, Tam A, Mathew R, Hixon J, Stahl M, Fritz CC, Seehra J, Somers WS, Structure. 2000 Aug 15;8(8):883-95. PMID:10997907
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
of the structures of the B. subtilis AcpS trimer (1f7t, in red, cyan, and yellow) the Mtb AcpS trimer (in lime, blue, and orange) and the Mycobacterium tuberculosis (Mtb) AcpS trimer (3hqj, in lime, blue, and orange) reveals that the Mtb AcpS structure is similar to those of other members of group I phosphopantetheine transferase (PPT) family. The is that the extended α3 helix of Mtb AcpS has open conformation. Such open conformation permits to the extended loop of one monomer (lime) to interact with adjacent monomer (blue). The considerably shorter α3 of one B. subtilis AcpS monomer (red) has closed conformation and this doesn't allow interaction with the neighboring monomer (cyan).
About this Structure
1F7T is a 6 chains structure of sequences from Bacillus subtilis. Full crystallographic information is available from OCA.
References
- Parris KD, Lin L, Tam A, Mathew R, Hixon J, Stahl M, Fritz CC, Seehra J, Somers WS. Crystal structures of substrate binding to Bacillus subtilis holo-(acyl carrier protein) synthase reveal a novel trimeric arrangement of molecules resulting in three active sites. Structure. 2000 Aug 15;8(8):883-95. PMID:10997907
- Dym O, Albeck S, Peleg Y, Schwarz A, Shakked Z, Burstein Y, Zimhony O. Structure-function analysis of the acyl carrier protein synthase (AcpS) from Mycobacterium tuberculosis. J Mol Biol. 2009 Nov 6;393(4):937-50. Epub 2009 Sep 3. PMID:19733180 doi:10.1016/j.jmb.2009.08.065
Page seeded by OCA on Wed Feb 18 00:47:32 2009
