title: Angiotensin II analogues encompassing 5,9- and 5,10-fused thiazabicycloalkane tripeptide mimetics.
abstract: A simple experimental procedure on solid phase for the construction of new tripeptidic 5,9- and 5,10-fused thiazabicycloalkane scaffolds that adopt beta-turns has been developed. This N-terminal-directed bicyclization, relying on masked aldehyde precursors derived from glutamic acid as key building blocks, provides a complement to the related bicyclization previously reported, where an aspartic acid-derived precursor was employed to induce cyclization toward the C-terminal end of the peptide. Thus, the regioselectivity of the bicyclization can be altered simply by varying the chain length of the incorporated aldehyde precursor. Four analogues of the hypertensive octapeptide angiotensin II, comprising the new scaffolds in the 3-5- and 5-7-positions, were synthesized. One of these conformationally constrained angiotensin II analogues exhibited AT(1) receptor affinity (K(i) = 750 nM). Results from theoretical conformational analysis of model compounds of the bicyclic tripeptide mimetics are presented, and they demonstrate that subtle differences in geometry have a strong impact on the affinity to the AT(1) receptor.
authors.affiliation: Department of Organic Pharmaceutical Chemistry, Uppsala University, SE-751 23 Uppsala, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Johannesson
authors.forename: G
authors.initials: G
authors.lastname: Lindeberg
authors.forename: W
authors.initials: W
authors.lastname: Tong
authors.forename: A
authors.initials: A
authors.lastname: Gogoll
authors.forename: B
authors.initials: B
authors.lastname: Synnergren
authors.forename: F
authors.initials: F
authors.lastname: Nyberg
authors.forename: A
authors.initials: A
authors.lastname: Karlén
authors.forename: A
authors.initials: A
authors.lastname: Hallberg
mesh_terms: D000804:Angiotensin II / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D001372:Aza Compounds / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism; D001667:Binding, Competitive; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism; D016466:CHO Cells; D006224:Cricetinae; D008958:Models, Molecular; D018716:Molecular Mimicry; D009842:Oligopeptides / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism; D017433:Protein Structure, Secondary; D011869:Radioligand Assay; D051381:Rats; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D011945:Receptors, Angiotensin / Q000378:metabolism; D013237:Stereoisomerism; D013329:Structure-Activity Relationship
chemical_list: D001372:Aza Compounds; D019086:Bridged Bicyclo Compounds, Heterocyclic; D009842:Oligopeptides; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D011945:Receptors, Angiotensin; D000804:Angiotensin II