Linked Life Data

18490168

Source:http://linkedlifedata.com/resource/pubmed/id/18490168

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
2008-6-13
pubmed:abstractText
Endomorphin-2 (EM-2) is a putative endogenous mu-opioid receptor ligand. To get insight into the important role of C-terminal amide group of EM-2, we investigated herein a series of EM-2 analogs by substitution of the C-terminal amide group with -NHNH(2), -NHCH(3), -N(CH(3))(2), -OCH(3), -OCH(2)CH(3), -OC(CH(3))(3), and -CH(2)-OH. Their binding affinity and bioactivity were determined and compared. Despite similar (analogs 1, 4, and 7) or decreased (analogs 2, 3,5, and 6) mu affinity in binding assays, all analogs showed low guinea pig ileum (GPI) and mouse vas deferens (MVD) potencies compared to their parent peptide. Interestingly, as for analogs 2 and 3 (a single and double N-methylation of C-terminal amide), the potency order with the K(i) (mu) values was 2>3; for the C-terminal esterified analogs 4-6, the potency order with the K(i) (mu) values was 4>5>6. Thus, we concluded that the steric hindrance of C-terminus might play an important role in opioid receptor affinity. We further investigated the conformational properties of these analogs by 1D and 2D (1)H NMR spectroscopy and molecular modeling. Evaluating the ratios of cis- and trans-isomers, aromatic interactions, dihedral angles, and stereoscopic views of the most convergent conformers, we found that modifications at the C-terminal amide group of EM-2 affected these analog conformations markedly, therefore changed the opioid receptor affinity and in vitro bioactivity.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
1464-3391
pubmed:author
pubmed:issnType
Electronic
pubmed:day
15
pubmed:volume
16
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6415-22
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Structure-activity study of endomorphin-2 analogs with C-terminal modifications by NMR spectroscopy and molecular modeling.
pubmed:affiliation
Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Biochemistry and Molecular Biology, School of Basic Medical Science, Lanzhou University, 222 Tianshui South Road, Lanzhou 730000, China.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't