The primary structure of inhibitor of cysteine proteinases from potato

Abstract

The complete amino acid sequence of the cysteine proteinase inhibitor from potato tubers was determined. The inhibitor is a single-chain protein having 180 amino acid residues. Its primary structure was elucidated by automatic degradation of the intact protein and sequence analysis of peptides generated by CNBr, trypsin and glycyl endopeptidase. A search through the protein sequence database showed homology to other plant proteinase inhibitors of different specificities and non-inhibitory proteins of M, around 20,000. On the basis of sequence homology, prediction of secondary structure and fold compatibility, based on a 3DlD score to the threedimensional profile of Erythrina caffra trypsin inhibitor, we suggest that the potato cysteine proteinase inhibitor belongs to the superfamily of proteins that have the same pattern of three-dimensional structure as soybean trypsin inhibitor. This superfamily would therefore include proteins that inhibit three different classes of proteinases -serine, cysteine and aspartic proteinases.Cysteine proteinase inhibitor; Amino acid sequence; Solunum tuberown; Soybean trypsin inhibitor superfamily

Clitocypin, a New Type of Cysteine Proteinase Inhibitor from Fruit Bodies of Mushroom Clitocybe nebularis

“…Five structurally different groups of protein cysteine proteinase inhibitors have been reported: cystatins (4), thyroglobulin type-1 domain inhibitors or thyropins (5), soybean trypsin inhibitor-like inhibitors of cysteine proteinases from potato (6), pineapple inhibitors of cysteine proteinases (7,8), and very recently, inhibitors of cysteine proteinases homologous to propeptide regions of cysteine proteinases (9). So far, only the mechanism of interaction of the cystatin superfamily of inhibitors has been elucidated (10,11), followed recently by that of thyropins (12), but overall there is very little information available on all other cysteine proteinase inhibitors concerning specificity, kinetics, and mode of binding.…”

The Primary Structure and Characterization of Carbohydrate Chains of the Extracellular Glycoprotein Proteinase Inhibitor from Latex of Carica Papaya

“…As for protease inhibitors, serine-proteinase inhibitors are dominant, but it is very interesting that potato [26] and tomato (Cathepsin D inhibitor protein-tomato, Werner, R., Guitton, M. & Muehlbach, H. P., EMBL Data Library accession no. S34387) inhibitors of cathepsin D, an aspartic proteinase, are clearly homologous to the trypsin inhibitor, and a potato cysteine proteinase inhibitor is also a homologue of soybean trypsin inhibitor [28]. Recently, it was found that the N-terminal sequence of a dehydroascorbate reductase from spinach chloroplast is similar to that of the soybean trypsin inhibitor, and that the reduced soybean trypsin inhibitor itself has the same enzyme activity [29].…”

β-Trefoil inhibitors – from the work of Kunitz onward

“…The cysteine protease inhibitor PCPI 8.3, isolated from potato tubers, was classifi ed as β -trefoil on the basis of the sequence homology (Krizaj et al , 1993 ). BbCI was fi rst classifi ed as a β -trefoil inhibitor by its sequence homology (de Oliveira et al , 2001 ) and later confi rmed by its crystal structure (Hansen et al , 2007 ).…”