PDBsum entry 2a1t

Oxidoreductase/electron transport

PDB id: 2a1t

Contents

Protein chains

386 a.a. *

313 a.a. *

239 a.a. *

Ligands

FAD ×5

AMP

Waters ×64

* Residue conservation analysis

PDB id:

2a1t

Name:

Oxidoreductase/electron transport

Title:

Structure of the human mcad:etf e165betaa complex

Structure:

Acyl-coa dehydrogenase, medium-chain specific, mitochondrial precursor. Chain: a, b, c, d. Synonym: mcad. Engineered: yes. Electron transfer flavoprotein alpha-subunit, mitochondrial precursor. Chain: r. Synonym: alpha-etf.

Source:

Homo sapiens. Human. Organism_taxid: 9606. Expressed in: escherichia coli. Expression_system_taxid: 562.

Biol. unit:

Hexamer (from PQS)

Resolution:

2.80Å R-factor: 0.203 R-free: 0.269

Authors:

H.S.Toogood,A.Van Thiel,N.S.Scrutton,D.Leys

Key ref:

H.S.Toogood et al. (2005). Stabilization of non-productive conformations underpins rapid electron transfer to electron-transferring flavoprotein. J Biol Chem, 280, 30361-30366. PubMed id: 15975918 DOI: 10.1074/jbc.M505562200

Date:

21-Jun-05 Release date: 05-Jul-05

Protein chains

P11310  (ACADM_HUMAN) -  Medium-chain specific acyl-CoA dehydrogenase, mitochondrial from Homo sapiens

Seq: 421 a.a.

Struc: 386 a.a.

Protein chain

P13804  (ETFA_HUMAN) -  Electron transfer flavoprotein subunit alpha, mitochondrial from Homo sapiens

Seq: 333 a.a.

Struc: 313 a.a.

Protein chain

P38117  (ETFB_HUMAN) -  Electron transfer flavoprotein subunit beta from Homo sapiens

Seq: 255 a.a.

Struc: 239 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: Chains A, B, C, D: E.C.1.3.8.7 - medium-chain acyl-CoA dehydrogenase.
• Reaction: a medium-chain 2,3-saturated fatty acyl-CoA + oxidized [electron-transfer flavoprotein] + H⁺ = a medium-chain (2E)-enoyl-CoA + reduced [electron- transfer flavoprotein]

DOI no: 10.1074/jbc.M505562200

J Biol Chem 280:30361-30366 (2005)

PubMed id: 15975918

Stabilization of non-productive conformations underpins rapid electron transfer to electron-transferring flavoprotein.

H.S.Toogood, A.van Thiel, N.S.Scrutton, D.Leys.

ABSTRACT

Crystal structures of protein complexes with electron-transferring flavoprotein (ETF) have revealed a dual protein-protein interface with one region serving as anchor while the ETF FAD domain samples available space within the complex. We show that mutation of the conserved Glu-165beta in human ETF leads to drastically modulated rates of interprotein electron transfer with both medium chain acyl-CoA dehydrogenase and dimethylglycine dehydrogenase. The crystal structure of free E165betaA ETF is essentially identical to that of wild-type ETF, but the crystal structure of the E165betaA ETF.medium chain acyl-CoA dehydrogenase complex reveals clear electron density for the FAD domain in a position optimal for fast interprotein electron transfer. Based on our observations, we present a dynamic multistate model for conformational sampling that for the wild-type ETF. medium chain acyl-CoA dehydrogenase complex involves random motion between three distinct positions for the ETF FAD domain. ETF Glu-165beta plays a key role in stabilizing positions incompatible with fast interprotein electron transfer, thus ensuring high rates of complex dissociation.

Selected figure(s)

Figure 4.
FIG. 4. Overview of the ETF·MCAD FAD domain interface in stereo. Residues involved in docking of the FAD domain to the MCAD surface are depicted in atom-colored sticks, with MCAD residues in teal or dark green, and ETF residues in blue-colored carbon atoms respectively. Waters located at the interface are represented by red spheres. Putative ionic and/or hydrogen bond interactions are depicted by dotted lines. Both redox cofactors are shown in atom-colored sticks (the MCAD FAD with yellow carbons and the ETF FAD with orange carbons).

Figure 5.
FIG. 5. Dynamic model for conformational sampling in the ETF-MCAD system. A, the three conformations of the FAD domain within the ETF·MCAD complex in stereo, color coding, and representation according to Fig. 3. The side chains of key glutamates Glu-165 (E165 ), Glu-212 (E212), and Arg-249 (R249 ) are indicated as atom-colored spheres. The MCAD and ETF FAD cofactors are colored in orange. B, the dynamic behavior of the ETF FAD domain in solution (blue) and in complex with MCAD (violet) is schematically represented. Key glutamate residues are indicated with red sticks, and Arg-249 is indicated with blue sticks. Flavin cofactors are represented by yellow hexagons.

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2005, 280, 30361-30366) copyright 2005.

Figures were selected by the author.