Angiotensinogen cleavage by renin: importance of a structurally constrained N-terminus

• Published in: FEBS letters Vol. 436; no. 2; pp. 267 - 270
• Main Authors: Streatfeild-James, Rosa M.A, Williamson, David, Pike, Robert N, Tewksbury, Duane, Carrell, Robin W, Coughlin, Paul B
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 02-10-1998
• Subjects: ACE, angiotensin-converting enzyme; alpha 1-Antitrypsin - chemistry; alpha 1-Antitrypsin - metabolism; Amino Acid Sequence; AngAT, Ang-Antitrypsin; Angiotensinogen; Angiotensinogen - chemistry; Angiotensinogen - metabolism; Catalysis; Cloning, Molecular; Cysteine; Disulfides; Escherichia coli; HPLC, high performance liquid chromatography; Humans; Hypertension; IPTG, isopropyl-β-d-thiogalactopyronoside; Kinetics; Models, Molecular; Molecular Sequence Data; Mutagenesis, Insertional; Ovalbumin - chemistry; Protein Conformation; Protein Structure, Secondary; Recombinant Fusion Proteins - chemistry; Recombinant Fusion Proteins - metabolism; Recombinant Proteins - metabolism; Renin - metabolism; Sequence Alignment; Sequence Homology, Amino Acid; Serpin; Hypertension; Serpin; Angiotensinogen; ACE, angiotensin-converting enzyme; AngAT, Ang-Antitrypsin; IPTG, isopropyl-β- d-thiogalactopyronoside; HPLC, high performance liquid chromatography
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(98)01145-4

Angiotensinogen, a plasma serpin, functions as a donor of the decapeptide angiotensin I, which is cleaved from the N-terminus by renin. To assess the contribution of the serpin framework to peptide cleavage we produced a chimaeric molecule of α
1-antitrypsin carrying the angiotensinogen N-terminus and determined the kinetic parameters for angiotensin I release. The
K
m for plasma angiotensinogen was 18-fold lower than for the chimaeric protein while the catalytic efficiency was four-fold higher. We also show that Cys-18 participates in a disulphide bond and propose that constraints on the N-terminus profoundly affect the interaction with renin.