PMID- 10529478
OWN - NLM
STAT- MEDLINE
DCOM- 19991206
LR  - 20191210
IS  - 0169-328X (Print)
IS  - 0169-328X (Linking)
VI  - 72
IP  - 2
DP  - 1999 Oct 1
TI  - Mutation of human mu opioid receptor extracellular "disulfide cysteine" residues 
      alters ligand binding but does not prevent receptor targeting to the cell plasma 
      membrane.
PG  - 195-204
AB  - The mu opioid receptor, a primary site of action in the brain for opioid
      neuropeptides and opiate drugs of abuse, is a member of the seven transmembrane, 
      G protein-coupled receptor (GPCR) superfamily. Two cysteine residues, one in each
      of the first two of three extracellular loops (ECLs), are highly conserved among 
      GPCRs, and there is direct or circumstantial evidence that the residues form a
      disulfide bond in many of these receptors. Such a bond would dramatically govern 
      the topology of the ECLs, and possibly affect the position of the
      membrane-spanning domains. Recent findings from several laboratories indicate the
      importance of the ECLs for opioid ligand selectivity. These conserved cysteine
      residues in the mu opioid receptor were studied using site-directed mutagenesis. 
      Little or no specific binding of radiolabled opiate alkaloid or opioid peptide
      agonists or antagonists was observed for receptors mutated at either "disulfide
      cysteine" residue. Each mutant mu opioid receptor was expressed in both
      transiently- and stably-transfected cells, in some cases at levels comparable to 
      the wild type receptor. The two point mutants possessing serine-for-cysteine
      substitutions were also observed to successfully reach the cell plasma membrane, 
      as evidenced by electron microscopy. Consistent with related work with other
      GPCRs, the mu opioid receptor apparently also employs the extracellular disulfide
      bond. This information now permits accurate molecular modeling of extracellular
      aspects of the receptor, including plausible scenarios of mu receptor docking of 
      opioid ligands known to require specific extracellular loop features for high
      affinity binding.
FAU - Zhang, P
AU  - Zhang P
AD  - Intramural Research Program, National Institute on Drug Abuse, Baltimore, MD
      21224, USA.
FAU - Johnson, P S
AU  - Johnson PS
FAU - Zollner, C
AU  - Zollner C
FAU - Wang, W
AU  - Wang W
FAU - Wang, Z
AU  - Wang Z
FAU - Montes, A E
AU  - Montes AE
FAU - Seidleck, B K
AU  - Seidleck BK
FAU - Blaschak, C J
AU  - Blaschak CJ
FAU - Surratt, C K
AU  - Surratt CK
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - Netherlands
TA  - Brain Res Mol Brain Res
JT  - Brain research. Molecular brain research
JID - 8908640
RN  - 0 (Ligands)
RN  - 0 (Narcotic Antagonists)
RN  - 0 (Nerve Tissue Proteins)
RN  - 0 (Peptides)
RN  - 0 (Receptors, Opioid, mu)
RN  - 100929-53-1 (Enkephalin, Ala(2)-MePhe(4)-Gly(5)-)
RN  - 36B82AMQ7N (Naloxone)
RN  - 48TCX9A1VT (Cystine)
RN  - 69344-77-0 (connective tissue-activating peptide)
RN  - 76I7G6D29C (Morphine)
RN  - K848JZ4886 (Cysteine)
SB  - IM
MH  - Amino Acid Substitution
MH  - Animals
MH  - CHO Cells
MH  - COS Cells
MH  - Chlorocebus aethiops
MH  - Cricetinae
MH  - Cricetulus
MH  - Cysteine/*chemistry
MH  - Cystine/chemistry
MH  - Enkephalin, Ala(2)-MePhe(4)-Gly(5)-/metabolism
MH  - Humans
MH  - Ligands
MH  - Morphine/metabolism
MH  - Mutagenesis, Site-Directed
MH  - Naloxone/metabolism
MH  - Narcotic Antagonists/metabolism
MH  - Nerve Tissue Proteins/chemistry/*genetics/metabolism
MH  - Peptides/metabolism
MH  - Point Mutation
MH  - Protein Binding
MH  - Protein Structure, Tertiary
MH  - Radioligand Assay
MH  - Receptors, Opioid, mu/chemistry/*genetics/metabolism
MH  - Structure-Activity Relationship
MH  - Transfection
EDAT- 1999/10/26 00:00
MHDA- 1999/10/26 00:01
CRDT- 1999/10/26 00:00
PHST- 1999/10/26 00:00 [pubmed]
PHST- 1999/10/26 00:01 [medline]
PHST- 1999/10/26 00:00 [entrez]
AID - S0169328X99002417 [pii]
AID - 10.1016/s0169-328x(99)00241-7 [doi]
PST - ppublish
SO  - Brain Res Mol Brain Res. 1999 Oct 1;72(2):195-204. doi:
      10.1016/s0169-328x(99)00241-7.