Evidence map›Paper›PMID 24513108›Full record

ArticleJournal of molecular biology2014

Flexible gates generate occluded intermediates in the transport cycle of LacY.

Lukas S Stelzl, Philip W Fowler, Mark S P Sansom, Oliver Beckstein

Open access · hybridAbstract read
In one paragraph

Article in Journal of molecular biology, 2014. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 32 papers.

0numbers the graph read from it
0cells of the map it votes in
32citing papers in PubMed
3.3field-weighted citation impact, top 8% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

32 citing papers in PubMed, 75 citations in OpenAlex.

  1. Article
  2. Article
  3. Article
  4. Review
  5. Article
  6. Review
  7. Review
  8. Article
  9. Article
  10. Article
  11. Article
  12. Article
  13. Article
  14. Article
  15. Article
  16. Review
  17. The contribution of modern EPR to structural biology.Emerging topics in life sciences · 2018
    Article
  18. Proton movement and coupling in the POT family of peptide transporters.Proceedings of the National Academy of Sciences of the United States of America · 2017
    Article
  19. Review
  20. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

4 authors at 2 institutions in 2 countries.

Lukas S Stelzl
Philip W Fowler
Mark S P Sansom
Oliver Beckstein
University of Oxford · GBArizona State University · US

Funding

Biotechnology and Biological Sciences Research Council B19456Biotechnology and Biological Sciences Research Council BB/H000267/1Biotechnology and Biological Sciences Research Council BB/I019855/1Biotechnology and Biological Sciences Research Council BB/L002558/1Biotechnology and Biological Sciences Research Council BBS/B/16011Biotechnology and Biological Sciences Research Council BEP17032Wellcome Trust
6 · The paper itself

Abstract

The major facilitator superfamily (MFS) transporter lactose permease (LacY) alternates between cytoplasmic and periplasmic open conformations to co-transport a sugar molecule together with a proton across the plasma membrane. Indirect experimental evidence suggested the existence of an occluded transition intermediate of LacY, which would prevent leaking of the proton gradient. As no experimental structure is known, the conformational transition is not fully understood in atomic detail. We simulated transition events from a cytoplasmic open conformation to a periplasmic open conformation with the dynamic importance sampling molecular dynamics method and observed occluded intermediates. Analysis of water permeation pathways and the electrostatic free-energy landscape of a solvated proton indicated that the occluded state contains a solvated central cavity inaccessible from either side of the membrane. We propose a pair of geometric order parameters that capture the state of the pathway through the MFS transporters as shown by a survey of available crystal structures and models. We present a model for the occluded state of apo-LacY, which is similar to the occluded crystal structures of the MFS transporters EmrD, PepTSo, NarU, PiPT and XylE. Our simulations are consistent with experimental double electron spin–spin distance measurements that have been interpreted to show occluded conformations. During the simulations, a salt bridge that has been postulated to be involved in driving the conformational transition formed. Our results argue against a simple rigid-body domain motion as implied by a strict “rocker-switch mechanism” and instead hint at an intricate coupling between two flexible gates.

Indexed as

Cell MembraneCrystallography, X-RayMembrane Transport ProteinsModels, MolecularMolecular Dynamics SimulationProtein ConformationProtein TransportSymporterslactose permeaseMembrane Transport ProteinsSymporters

Identifiers

PMID24513108
PMCPMC3905165
OpenAlexW1970143564

What OpenQuestion holds

Textmetadata
LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.