tailieunhanh - Báo cáo khoa học: Inhibitory activity of double-sequence analogues of trypsin inhibitor SFTI-1 from sunflower seeds: an example of peptide splicing

Four 28-amino acid peptides were synthesized whose sequences comprised two molecules of trypsin inhibitor sunflower trypsin inhibitor 1 (SFTI-1) bound through a peptide bond. The peptides in their reactive positions (5 and 19 of the peptide chain) contain two Lys ([KK]BiSFTI-1) and two Phe ([FF]BiSFTI-1) residues, along with a combination of the amino acid residues named thereafter [KF]BiSFTI-1 and [FK]BiSFTI-1. | ỊFEBS Journal Inhibitory activity of double-sequence analogues of trypsin inhibitor SFTI-1 from sunflower seeds an example of peptide splicing Anna Legowska1 Adam Lesner1 Elzbieta Bulak1 Anna Jaskiewicz1 Adam Sieradzan1 Marzena Cydzik2 Piotr Stefanowicz2 Zbigniew Szewczuk2 and Krzysztof Rolka1 1 Faculty of Chemistry University of Gdansk Poland 2 Faculty of Chemistry University of Wroctaw Poland Keywords inhibitors mass spectrometry peptide splicing serine proteinases SFTI-1 Correspondence A. Legowska Faculty of Chemistry University of Gdansk Sobieskiego 18 80-952 Gdansk Poland Fax 48 5852 3472 Tel 48 5852 3359 E-mail legowska@ Received 4 February 2010 revised 10 March 2010 accepted 15 March 2010 doi Four 28-amino acid peptides were synthesized whose sequences comprised two molecules of trypsin inhibitor sunflower trypsin inhibitor 1 SFTI-1 bound through a peptide bond. The peptides in their reactive positions 5 and 19 of the peptide chain contain two Lys KK BiSFTI-1 and two Phe FF BiSFTI-1 residues along with a combination of the amino acid residues named thereafter KF BiSFTI-1 and FK BiSFTI-1. Association constants of the analogues determined with trypsin and chymotrypsin respectively indicated that they were potent inhibitors of cognate proteinases. An MS study of the associates revealed that incubation of the compounds with the proteinases resulted in cutting out a fragment of the peptide chain to restore the native monocyclic molecule of SFTI-1 or its analogue Phe5 SFTI-1. This process analogous to that of the DNA and protein splicing can be referred to as peptide splicing . Introduction Trypsin inhibitor SFTI-1 the smallest member of the family of Bowman-Birk inhibitors BBIs has been found in sunflower seeds 1 . This homodetic peptide consists of 14 amino acid residues and its structure is stabilized by a disulfide bridge Fig. 1 . The reactive site P1-P1 of this peptide is located between Lys5-Ser6. As a result