Wound-induced proteinase inhibitors from tomato leaves. II. The cDNA-deduced primary structure of pre-inhibitor II.

J S Graham,G Pearce,J Merryweather,K Titani,L H Ericsson,C A Ryan

doi:10.1016/s0021-9258(18)88818-4

Abstract

A cDNA containing the complete amino acid-coding region of wound-induced tomato Inhibitor II was constructed in the plasmid pUC9. The open reading frame codes for 148 amino acids including a 25-amino acid signal sequence preceding the N-terminal lysine of the mature Inhibitor II. The Inhibitor II sequence exhibits two domains, one domain having a trypsin inhibitory site and the other a chymotrypsin inhibitory site, apparently evolved from a smaller gene by a process of gene duplication and elongation. The amino acid sequence of tomato leaf Inhibitor II exhibits homology with two small proteinase inhibitors isolated from potato tuber and an inhibitor from eggplant. The small potato tuber inhibitors are homologous with 33 amino acids of the N-terminal domain and 19 amino acids from the C-terminal domain. Two identical nucleotide sequences of Inhibitor II cDNA in the 3' noncoding region were present that were also found in an Inhibitor I cDNA. These include an atypical polyadenylation signal, AATAAG, and a 10-base palindromic sequence, CATTATAATG, for which no function is yet known.

Highlights

From the Institute of Biological Chemistry and Biochemistry/Biophysics Program, Washington State University, Pullman, Washington 99164, SChiron Corporation, Emeryville, California94608, and the VDepartment of Biochemistry, University of Washington, Seattle, Washington 98195
Two identical nucleotide sequences ofInhibitor I1cDNA inthe 3' noncoding region were present that were found in an Inhib- Materials-Tomato plants
The characterization of a cDNA prepared from wound-induced Inhibitor I mRNA (7)and have deduced the amino acid sequence of Inhibitor I and of its processing after synthesis

Summary

Introduction

The characterization of a cDNA prepared from wound-induced Inhibitor I mRNA (7)and have deduced the amino acid sequence of Inhibitor I and of its processing after synthesis. Screening of Tomato cDNA Library for Inhibitor I I Sequences-Fifteen hundred recombinant clones were initially screened as described (7).A second screening of 130 wound-positive clones was accumulates in leaves coordinately with Inhibitor I, M , = performed utilizing a 17-nucleotide oligomer mixture prepared as previously described and corresponding to the 64 possible coding

Results

Conclusion