1. Isolation and identification of glycosylphosphatidylinositol-anchored arabinogalactan proteins and novel beta-glucosyl Yariv-reactive proteins from seeds of rice (Oryza sativa)
Kiyoshi Mashiguchi, Isomaro Yamaguchi, Yoshihito Suzuki Plant Cell Physiol. 2004 Dec;45(12):1817-29. doi: 10.1093/pcp/pch208.
Arabinogalactan proteins (AGPs) are highly glycosylated extracellular glycoproteins playing important roles in plant growth and development. We have previously reported the possibility that AGPs are involved in the induction of alpha-amylase by gibberellin (GA) in barley aleurone layers by using the beta-glucosyl Yariv reagent (beta-GlcY), which has been presumed to specifically bind AGPs. In this present study, we isolated beta-GlcY-reactive proteins from rice bran rich in aleurone cells. The N-terminal sequences of classical AGP and AG peptides were determined from hydrophilic fractions obtained by reversed phase HPLC. Interestingly, a novel non-specific lipid transfer protein-like protein (OsLTPL1) and a novel early nodulin-like protein (OsENODL1) were also identified in the more hydrophobic fractions from HPLC as beta-GlcY-reactive proteins. Expression analysis of the genes coding for these proteins was performed. While classical AGP, AG peptides and OsLTPL1 were expressed in various parts of rice, OsENODL1 showed temporally and spatially specific expression in the aleurone layers. This new beta-GlcY-reactive protein is a promising candidate for the extracellular signaling factors of GA action in cereal seeds. Furthermore, the possibility that proteins with the AG glycomodule might react with beta-GlcY may broaden the definition of AGPs.
2. Isolation and characterization of a novel thermostable non-specific lipid transfer protein-like antimicrobial protein from motherwort (Leonurus japonicus Houtt) seeds
Xingyong Yang, Jun Li, Xianbi Li, Rong She, Yan Pei Peptides. 2006 Dec;27(12):3122-8. doi: 10.1016/j.peptides.2006.07.019. Epub 2006 Sep 18.
In screening for potent antimicrobial proteins from plant seeds, a novel heat-stable antimicrobial protein, designated LJAMP2, was purified from seeds of the motherwort (Leonurus japonicus Houtt), a medicine herb, with a procedure involving cation exchange chromatography on a CM FF column, and reverse phase HPLCs on C8 column and C18 column. LJAMP2 exhibited a molecular mass of 6.2 kDa determined. Automated Edman degradation determined the partial N-terminal sequence of LJAMP2 to be NH2-AIGCNTVASKMAPCLPYVTGKGPLGGCCGGVKGLIDAARTTPDRQAVCNCLKTLAKSYSG, which displays homology with plant non-specific lipid transfer proteins (nsLTPs). In vitro bioassays showed that LJAMP2 inhibits the growth of a variety of microbes, including filamentous fungi, bacteria and yeast. The growth of three phytopathogenic fungi, Alternaria brassicae, Botrytis maydis, and Rhizoctonia cerealis, are inhibited at 7.5 microM of LJAMP2, whereas Bacillus subtilis is about 15 microM. The IC(50) of LJAMP2 for Aspergillus niger, B. maydis, Fusarium oxysporum, Penicillium digitatum and Saccharomyces cerevisiae are 5.5, 6.1, 9.3, 40.0, and 76.0 microM, respectively.
