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PDBsum entry 4nab
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PDB id:
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Hydrolase
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Title:
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Structure of the (sr)ca2+-atpase mutant e309q in the ca2-e1-mgamppcp form
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Structure:
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Sarcoplasmic/endoplasmic reticulum calcium atpase 1. Chain: a. Synonym: serca1, sr ca(2+)-atpase 1, calcium pump 1, calcium- transporting atpase sarcoplasmic reticulum type, fast twitch skeletal muscle isoform, endoplasmic reticulum class 1/2 ca(2+) atpase. Engineered: yes. Mutation: yes
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Source:
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Oryctolagus cuniculus. European rabbit,japanese white rabbit,domestic rabbit,rabbits. Organism_taxid: 9986. Gene: atp2a1. Expressed in: saccharomyces cerevisiae. Expression_system_taxid: 4932
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Resolution:
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3.50Å
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R-factor:
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0.219
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R-free:
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0.266
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Authors:
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M.Bublitz,J.D.Clausen,B.Arnou,C.Montigny,C.Jaxel,P.Nissen,J.V.Moller, J.P.Andersen,M.Le Maire
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Key ref:
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J.D.Clausen
et al.
(2013).
SERCA mutant E309Q binds two Ca(2+) ions but adopts a catalytically incompetent conformation.
Embo J,
32,
3231-3243.
PubMed id:
DOI:
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Date:
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22-Oct-13
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Release date:
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18-Dec-13
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PROCHECK
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Headers
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References
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P04191
(AT2A1_RABIT) -
Sarcoplasmic/endoplasmic reticulum calcium ATPase 1 from Oryctolagus cuniculus
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Seq:
Struc:
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1001 a.a.
830 a.a.*
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Key: |
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PfamA domain |
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Secondary structure |
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CATH domain |
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*
PDB and UniProt seqs differ
at 2 residue positions (black
crosses)
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Enzyme class:
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E.C.7.2.2.10
- P-type Ca(2+) transporter.
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Reaction:
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Ca2+(in) + ATP + H2O = Ca2+(out) + ADP + phosphate + H+
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Ca(2+)(in)
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+
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ATP
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+
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H2O
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=
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Ca(2+)(out)
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+
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ADP
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+
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phosphate
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+
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H(+)
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Cofactor:
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Mg(2+)
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Molecule diagrams generated from .mol files obtained from the
KEGG ftp site
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DOI no:
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Embo J
32:3231-3243
(2013)
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PubMed id:
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SERCA mutant E309Q binds two Ca(2+) ions but adopts a catalytically incompetent conformation.
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J.D.Clausen,
M.Bublitz,
B.Arnou,
C.Montigny,
C.Jaxel,
J.V.Møller,
P.Nissen,
J.P.Andersen,
M.le Maire.
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ABSTRACT
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The sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) couples ATP hydrolysis to
transport of Ca(2+). This directed energy transfer requires cross-talk between
the two Ca(2+) sites and the phosphorylation site over 50 Å distance. We have
addressed the mechano-structural basis for this intramolecular signal by
analysing the structure and the functional properties of SERCA mutant E309Q.
Glu(309) contributes to Ca(2+) coordination at site II, and a consensus has been
that E309Q only binds Ca(2+) at site I. The crystal structure of E309Q in the
presence of Ca(2+) and an ATP analogue, however, reveals two occupied Ca(2+)
sites of a non-catalytic Ca2E1 state. Ca(2+) is bound with micromolar affinity
by both Ca(2+) sites in E309Q, but without cooperativity. The Ca(2+)-bound
mutant does phosphorylate from ATP, but at a very low maximal rate.
Phosphorylation depends on the correct positioning of the A-domain, requiring a
shift of transmembrane segment M1 into an 'up and kinked position'. This
transition is impaired in the E309Q mutant, most likely due to a lack of charge
neutralization and altered hydrogen binding capacities at Ca(2+) site II.
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Links
