Characterization and cDNA cloning of two glycine- and histidine-rich antimicrobial peptides from the roots of shepherd's purse, Capsella bursa-pastoris

Plant Mol Biol. 2000 Sep;44(2):187-97. doi: 10.1023/a:1006431320677.

Abstract

Two novel antimicrobial peptides were isolated and characterized from the roots of shepherd's purse, Capsella bursa-pastoris. These antimicrobial peptides, named shepherin I and shepherin II, consist of 28 and 38 amino acids, respectively, and are glycine- and histidine-rich peptides. Shepherin I and shepherin II have 67.9% and 65.8% (mol/mol) glycine, respectively, and 28.6% and 21.1% (mol/mol) histidine, respectively. Both shepherins have a Gly-Gly-His motif. These antimicrobial peptides exhibit antimicrobial activity against Gram-negative bacteria and fungi. Circular dichroism spectra of shepherin I and shepherin II showed that shepherin I and shepherin II in 50% trifluoroethanol have 66.7% and 75% random coils, respectively, without any alpha-helices. cDNA sequence analysis revealed that shepherin I and shepherin II are produced from a single polypeptide, designated shep-GRP, consisting of 120 amino acids; shep-GRP has five distinct domains, an amino-terminal putative signal peptide, a shepherin I, a linker dipeptide, a shepherin II and a carboxy-terminal peptide. Southern blot analysis indicates that the gene encoding shepherins belongs to a low-complexity gene family. Northern blot analysis revealed that transcripts of shep-GRP are present in roots but not in leaves and stems.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Anti-Bacterial Agents / chemistry
  • Anti-Bacterial Agents / isolation & purification
  • Anti-Bacterial Agents / pharmacology
  • Bacteria / drug effects
  • Bacteria / growth & development
  • Base Sequence
  • Blotting, Northern
  • Blotting, Southern
  • Brassicaceae / genetics*
  • Cell Division / drug effects
  • Circular Dichroism
  • Cloning, Molecular
  • DNA, Complementary / chemistry
  • DNA, Complementary / genetics*
  • DNA, Plant / genetics
  • Fungi / drug effects
  • Fungi / growth & development
  • Gene Expression Regulation, Plant
  • Glycine / genetics
  • Histidine / genetics
  • Microbial Sensitivity Tests
  • Molecular Sequence Data
  • Peptides
  • Plant Proteins / genetics*
  • Plant Proteins / pharmacology
  • Plant Roots / genetics*
  • Protein Isoforms / genetics
  • Protein Isoforms / pharmacology
  • RNA, Plant / genetics
  • RNA, Plant / metabolism
  • Sequence Alignment
  • Sequence Analysis, DNA
  • Sequence Analysis, Protein
  • Sequence Homology, Amino Acid
  • Tissue Distribution

Substances

  • Anti-Bacterial Agents
  • DNA, Complementary
  • DNA, Plant
  • GRP protein, Capsella bursa-pastoris
  • Peptides
  • Plant Proteins
  • Protein Isoforms
  • RNA, Plant
  • Histidine
  • Glycine

Associated data

  • GENBANK/AF180444