PMID- 19141613
OWN - NLM
STAT- MEDLINE
DCOM- 20090514
LR  - 20211020
IS  - 0021-9258 (Print)
IS  - 1083-351X (Electronic)
IS  - 0021-9258 (Linking)
VI  - 284
IP  - 12
DP  - 2009 Mar 20
TI  - Surface accessibility and conformational changes in the N-terminal domain of type 
      I inositol trisphosphate receptors: studies using cysteine substitution 
      mutagenesis.
PG  - 8093-102
LID - 10.1074/jbc.M806932200 [doi]
AB  - To identify surface-accessible residues and monitor conformational changes of the 
      type I inositol 1,4,5-trisphosphate receptor protein in membranes, we have 
      introduced 10 cysteine substitutions into the N-terminal ligand-binding domain. 
      The reactivity of these mutants with progressively larger maleimide-polyethylene 
      glycol derivatives (MPEG) was measured using a gel shift assay of tryptic 
      fragments. The results indicate that the mutations fall into four categories as 
      follows: sites that are highly accessible based on reactivity with the largest 
      20-kDa MPEG (S2C); sites that are moderately accessible based on reactivity only 
      with 5-kDa MPEG (S6C, S7C, A189C, and S277C); sites whose accessibility is 
      markedly enhanced by Ca(2+) (S171C, S277C, and A575C); and sites that are 
      inaccessible irrespective of incubation conditions (S217C, A245C, and S436C). The 
      stimulation of accessibility induced by Ca(2+) at the S277C site occurred with an 
      EC(50) of 0.8 mum and was mimicked by Sr(2+) but not Ba(2+). Inositol 
      1,4,5-trisphosphate alone did not affect reactivity of any of the mutants in the 
      presence or absence of Ca(2+). The data are interpreted using crystal structures 
      and EM reconstructions of the receptor. Our data identify N-terminal regions of 
      the protein that become exposed upon Ca(2+) binding and suggest possible 
      orientations of the suppressor and ligand-binding domains that have implications 
      for the mechanism of gating of the channel.
FAU - Anyatonwu, Georgia
AU  - Anyatonwu G
AD  - Department of Pathology, Thomas Jefferson University, Philadelphia, Pennsylvania 
      19107, USA.
FAU - Joseph, Suresh K
AU  - Joseph SK
LA  - eng
GR  - DK34804/DK/NIDDK NIH HHS/United States
GR  - T32-AA07463/AA/NIAAA NIH HHS/United States
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
DEP - 20090113
PL  - United States
TA  - J Biol Chem
JT  - The Journal of biological chemistry
JID - 2985121R
RN  - 0 (Inositol 1,4,5-Trisphosphate Receptors)
RN  - 0 (Metals)
RN  - 3WJQ0SDW1A (Polyethylene Glycols)
RN  - 9004-74-4 (monomethoxypolyethylene glycol)
RN  - K848JZ4886 (Cysteine)
SB  - IM
MH  - Amino Acid Substitution
MH  - Animals
MH  - Binding Sites/physiology
MH  - COS Cells
MH  - Chlorocebus aethiops
MH  - Cysteine/chemistry/genetics/metabolism
MH  - Inositol 1,4,5-Trisphosphate Receptors/*chemistry/genetics/metabolism
MH  - Ion Channel Gating/physiology
MH  - Metals/chemistry
MH  - Mutagenesis, Site-Directed
MH  - Polyethylene Glycols/chemistry
MH  - Protein Structure, Tertiary/physiology
MH  - Rats
PMC - PMC2658103
EDAT- 2009/01/15 09:00
MHDA- 2009/05/15 09:00
PMCR- 2010/03/20
CRDT- 2009/01/15 09:00
PHST- 2009/01/15 09:00 [entrez]
PHST- 2009/01/15 09:00 [pubmed]
PHST- 2009/05/15 09:00 [medline]
PHST- 2010/03/20 00:00 [pmc-release]
AID - S0021-9258(20)32522-9 [pii]
AID - 8093 [pii]
AID - 10.1074/jbc.M806932200 [doi]
PST - ppublish
SO  - J Biol Chem. 2009 Mar 20;284(12):8093-102. doi: 10.1074/jbc.M806932200. Epub 2009 
      Jan 13.