PDBsum entry 1f7l

Transferase

PDB id: 1f7l

Contents

Protein chain

118 a.a. *

Ligands

COA

Metals

_CA ×2

_CL

Waters ×98

* Residue conservation analysis

PDB id:

1f7l

Name:

Transferase

Title:

Holo-(acyl carrier protein) synthase in complex with coenzyme a at 1.5a

Structure:

Holo-(acyl carrier protein) synthase. Chain: a. Engineered: yes. Mutation: yes

Source:

Bacillus subtilis. Organism_taxid: 1423. Expressed in: escherichia coli. Expression_system_taxid: 562.

Biol. unit:

Trimer (from PDB file)

Resolution:

1.50Å R-factor: 0.185 R-free: 0.201

Authors:

K.D.Parris,L.Lin,A.Tam,R.Mathew,J.Hixon,M.Stahl,C.C.Fritz,J.Seehra, W.S.Somers

Key ref:

K.D.Parris et al. (2000). 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, 8, 883-895. PubMed id: 10997907 DOI: 10.1016/S0969-2126(00)00178-7

Date:

27-Jun-00 Release date: 27-Jun-01

Protein chain

P96618  (ACPS_BACSU) -  Holo-[acyl-carrier-protein] synthase from Bacillus subtilis (strain 168)

Seq: 121 a.a.

Struc: 118 a.a.*

* PDB and UniProt seqs differ at 2 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.2.7.8.7 - holo-[acyl-carrier-protein] synthase.
• Reaction: apo-[ACP] + CoA = holo-[ACP] + adenosine 3',5'-bisphosphate + H⁺

apo-[ACP] + CoA (Bound ligand (Het Group name = COA) corresponds exactly) = holo-[ACP] + adenosine 3',5'-bisphosphate + H(+)

• Cofactor: Mg(2+)

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

Added reference

DOI no: 10.1016/S0969-2126(00)00178-7

Structure 8:883-895 (2000)

PubMed id: 10997907

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.

K.D.Parris, L.Lin, A.Tam, R.Mathew, J.Hixon, M.Stahl, C.C.Fritz, J.Seehra, W.S.Somers.

ABSTRACT

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.

Selected figure(s)

Figure 6.
Figure 6. The mechanism that can be derived from the crystal structures in this study. The metal-bound water molecule removes the hydrogen from Ser36, converting it into a nucleophile and thereby initiating P-pant transfer and activation of ACP.

The above figure is reprinted by permission from Cell Press: Structure (2000, 8, 883-895) copyright 2000.

Figure was selected by an automated process.