Crystal structure of the Escherichia coli ATPgS-bound MetNI methionine ABC transporter in complex with its MetQ binding proteinCrystal structure of the Escherichia coli ATPgS-bound MetNI methionine ABC transporter in complex with its MetQ binding protein

Structural highlights

6cvl is a 5 chain structure with sequence from Escherichia coli K-12. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 2.953Å
Ligands:, ,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

METN_ECOLI Part of the ABC transporter complex MetNIQ involved in methionine import. Responsible for energy coupling to the transport system (Probable). It has also been shown to be involved in formyl-L-methionine transport.[1] [2]

Publication Abstract from PubMed

The Escherichia coli methionine ABC transporter MetNI exhibits both high-affinity transport toward l-methionine and broad specificity toward methionine derivatives, including d-methionine. In this work, we characterize the transport of d-methionine derivatives by the MetNI transporter. Unexpectedly, the N229A substrate-binding deficient variant of the cognate binding protein MetQ was found to support high MetNI transport activity toward d-selenomethionine. We determined the crystal structure at 2.95 A resolution of the ATPgammaS-bound MetNIQ complex in the outward-facing conformation with the N229A apo MetQ variant. This structure revealed conformational changes in MetQ providing substrate access through the binding protein to the transmembrane translocation pathway. MetQ likely mediates uptake of methionine derivatives through two mechanisms: in the methionine-bound form delivering substrate from the periplasm to the transporter (the canonical mechanism) and in the apo form by facilitating ligand binding when complexed to the transporter (the noncanonical mechanism). This dual role for substrate-binding proteins is proposed to provide a kinetic strategy for ABC transporters to transport both high- and low-affinity substrates present in a physiological concentration range.

Noncanonical role for the binding protein in substrate uptake by the MetNI methionine ATP Binding Cassette (ABC) transporter.,Nguyen PT, Lai JY, Lee AT, Kaiser JT, Rees DC Proc Natl Acad Sci U S A. 2018 Nov 6;115(45):E10596-E10604. doi:, 10.1073/pnas.1811003115. Epub 2018 Oct 23. PMID:30352853[3]

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

References

  1. Gal J, Szvetnik A, Schnell R, Kalman M. The metD D-methionine transporter locus of Escherichia coli is an ABC transporter gene cluster. J Bacteriol. 2002 Sep;184(17):4930-2. PMID:12169620
  2. Zhang Z, Feige JN, Chang AB, Anderson IJ, Brodianski VM, Vitreschak AG, Gelfand MS, Saier MH Jr. A transporter of Escherichia coli specific for L- and D-methionine is the prototype for a new family within the ABC superfamily. Arch Microbiol. 2003 Aug;180(2):88-100. Epub 2003 Jun 19. PMID:12819857 doi:http://dx.doi.org/10.1007/s00203-003-0561-4
  3. Nguyen PT, Lai JY, Lee AT, Kaiser JT, Rees DC. Noncanonical role for the binding protein in substrate uptake by the MetNI methionine ATP Binding Cassette (ABC) transporter. Proc Natl Acad Sci U S A. 2018 Nov 6;115(45):E10596-E10604. doi:, 10.1073/pnas.1811003115. Epub 2018 Oct 23. PMID:30352853 doi:http://dx.doi.org/10.1073/pnas.1811003115

6cvl, resolution 2.95Å

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