A Conserved Asparagine in a P-type Proton Pump Is Required for Efficient Gating of Protons

Ekberg, Kira; Wielandt, Alex Green; Buch-Pedersen, Morten J.; Palmgren, Michael G.

doi:10.1074/jbc.m112.417345

Cited by 15 publications

(13 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similarly, occlusion of the Asp684-Asn106 pair is likely to increase the pKa of Asp684 and therefore stabilize protonation (Buch-Pedersen et al, 2009 ). The important functional role of Asn106 was further highlighted by mutational studies (Ekberg et al, 2013 ). Various point mutations (N106A, N106D, N106K, N106Q, and N106T) could complement a PMA1 knockout and maintain a membrane potential.…”

Section: Structural and Functional Analysis Of Aha2mentioning

confidence: 97%

Improved Model of Proton Pump Crystal Structure Obtained by Interactive Molecular Dynamics Flexible Fitting Expands the Mechanistic Model for Proton Translocation in P-Type ATPases

et al. 2017

View full text Add to dashboard Cite

The plasma membrane H+-ATPase is a proton pump of the P-type ATPase family and essential in plants and fungi. It extrudes protons to regulate pH and maintains a strong proton-motive force that energizes e.g., secondary uptake of nutrients. The only crystal structure of a H+-ATPase (AHA2 from Arabidopsis thaliana) was reported in 2007. Here, we present an improved atomic model of AHA2, obtained by a combination of model rebuilding through interactive molecular dynamics flexible fitting (iMDFF) and structural refinement based on the original data, but using up-to-date refinement methods. More detailed map features prompted local corrections of the transmembrane domain, in particular rearrangement of transmembrane helices 7 and 8, and the cytoplasmic N- and P-domains, and the new model shows improved overall quality and reliability scores. The AHA2 structure shows similarity to the Ca2+-ATPase E1 state, and provides a valuable starting point model for structural and functional analysis of proton transport mechanism of P-type H+-ATPases. Specifically, Asp684 protonation associated with phosphorylation and occlusion of the E1P state may result from hydrogen bond interaction with Asn106. A subsequent deprotonation associated with extracellular release in the E2P state may result from an internal salt bridge formation to an Arg655 residue, which in the present E1 state is stabilized in a solvated pocket. A release mechanism based on an in-built counter-cation was also later proposed for Zn2+-ATPase, for which structures have been determined in Zn2+ released E2P-like states with the salt bridge interaction formed.

show abstract

Section: Structural and Functional Analysis Of Aha2mentioning

confidence: 97%

Improved Model of Proton Pump Crystal Structure Obtained by Interactive Molecular Dynamics Flexible Fitting Expands the Mechanistic Model for Proton Translocation in P-Type ATPases

et al. 2017

View full text Add to dashboard Cite

show abstract

“…In H + -ATPases, AtAHA2-Asp684 participates in proton transfer to the extracellular side and Arg655 has been proposed to stimulate proton release from Asp684 and prevent re-protonation 18 . Phe210 of SsZntA separates the electronegative ion entry funnel from the membranous Zn 2+ site and overlaps with AtAHA2-Asn106, which stabilizes the protonated AHA2-Asp684 (Ref 18) and blocks intracellular proton exchange 24 . In Fig.…”

Section: Figuresmentioning

confidence: 99%

“…We note that the equivalent residue to SsZntA Phe210 in H + -ATPases, Asn106, is a gatekeeper for proton entry (Fig. 3c) 18,24 . With conformational changes anticipated for the shift to the E1 states, Zn 2+ may thus be guided through the funnel and led directly to Cys392 of the high-affinity site, capped by Met148 and Phe210.…”

mentioning

confidence: 99%

Structure and mechanism of Zn2+-transporting P-type ATPases

Wang

Sitsel

Meloni

et al. 2014

Nature

109

171

View full text Add to dashboard Cite

Zinc is an essential micronutrient for all living organisms, required for signaling and proper function of a range of proteins involved in e.g. DNA-binding and enzymatic catalysis 1 . In prokaryotes and photosynthetic eukaryotes Zn 2+ -transporting P-type ATPases of class IB (ZntA) are crucial for cellular redistribution and detoxification of Zn 2+ and related elements 2,3 . Here we present crystal structures representing the phosphoenzyme ground state (E2P) and a dephosphorylation intermediate (E2.P i ) of ZntA from Shigella sonnei, determined at 3.2 and 2.7 Å resolution, respectively. The structures reveal a similar fold as the Cu + -ATPases with an amphipathic helix at the membrane interface. A conserved electronegative funnel connects this region to the intramembranous high-affinity ion-binding site and may promote specific uptake of cellular Zn 2+ ions. The E2P structure displays a wide extracellular release pathway reaching the invariant residues at the high-affinity site, including Cys392, Cys394 and Asp714. The pathway closes in the E2.P i state where Asp714 interacts with the conserved Lys693, which possibly stimulates Zn 2+ release as a built-in counter-ion, as also proposed for H + -ATPases. Indeed, transport studies in liposomes provide experimental support for ZntA activity without counter-

show abstract

“…S5). The Phe residues are in the same position as an N106 in H + P-type ATPases proposed to act as a gatekeeper (Pedersen et al , 2007; Ekberg et al , 2013). Together, the V154 and F177 residues of HMA4 might fulfill this function, preventing Zn 2+ release back outside upon entry.…”

Section: Discussionmentioning

confidence: 99%

Homology modeling andin vivofunctional characterization of the zinc permeation pathway in a heavy metal P-type ATPase

Lekeux

Crowet

Nouet

et al. 2018

Journal of Experimental Botany

View full text Add to dashboard Cite

show abstract

A Conserved Asparagine in a P-type Proton Pump Is Required for Efficient Gating of Protons

Cited by 15 publications

References 48 publications

Improved Model of Proton Pump Crystal Structure Obtained by Interactive Molecular Dynamics Flexible Fitting Expands the Mechanistic Model for Proton Translocation in P-Type ATPases

Improved Model of Proton Pump Crystal Structure Obtained by Interactive Molecular Dynamics Flexible Fitting Expands the Mechanistic Model for Proton Translocation in P-Type ATPases

Structure and mechanism of Zn2+-transporting P-type ATPases

Homology modeling andin vivofunctional characterization of the zinc permeation pathway in a heavy metal P-type ATPase

Contact Info

Product

Resources

About