Purification and characterisation of a jacalin-related, coleoptile specific lectin from Hordeum vulgare

Abstract

A plant lectin was isolated from barley (Hordeum vulgare) coleoptiles using acidic extraction and different chromatographic methods. Sequencing of more than 50% of the protein sequence by Edman degradation confirmed a full-length cDNA clone. The subsequently identified open reading frame encodes for a 15 kDa protein which could be found in the soluble fraction of barley coleoptiles. This protein exhibited specificity towards mannose sugar and is therefore, accordingly named as Horcolin (Hordeum vulgare coleoptile lectin). Database searches performed with the Horcolin protein sequence revealed a sequence and structure homology to the lectin family of jacalin-related lectins. Together with its affinity towards mannose, Horcolin is now identified as a new member of the mannose specific subgroup of jacalin-related lectins in monocot species. Horcolin shares a high amino acid homology to the highly light-inducible protein HL#2 and, in addition to two methyl jasmonic acid-inducible proteins of 32.6 and 32.7 kDa where the jasmonic acid-inducible proteins are examples of bitopic chimerolectins containing a dirigent and jacalin-related domain. Immunoblot analysis with a cross-reactive anti-HL#2 antibody in combination with Northern blot analysis of the Horcolin cDNA revealed tissue specific expression of Horcolin in the coleoptiles. The function of Horcolin is discussed in the context of its particular expression in coleoptiles and is then compared to other lectins, which apparently share a related response to biotic or abiotic stress factors.

Biochemical analyses of the cement float of the goose barnacleDosima fascicularis– a preliminary study

“…2D-PAGE for each strip was performed at 200 V, 50 mA for 50 min in precast 10-20% polyacrylamide ready gels for IPG strips (Bio-Rad). Proteins were visualised by overnight staining in Page Blue™ and destained in distilled water (Grunwald et al 2007). …”

Isolation of a low-sulfur tolerance gene from Eichhornia crassipes using a functional gene-mining approach

“…This rice lectin was not detected in untreated plants while detected in roots subjected to salt, drought and heat stress, or treated with jasmonic acid and abscisic acid (Garcia et al 1998;de Souza et al 2003). Horcolin (H. vulgare coleoptile lectin), a jacalin-related lectin from barley coleoptiles (Grunwald et al 2007) was exclusively expressed in both light-or dark-grown coleoptiles but not in leaves or roots, and also up-regulated under salt stress. In Arabidopsis, the RTM1 with similarities to jacalin-related proteins and MBP was shown to control long-distance movement of tobacco etch virus (Chisholm et al 2000).…”

“…JRLs are widely spread in plant kingdom such as Calsepa from hedge bindweed (Calystegia Sepium;Van Damme et al 1996), Heltuba from H. tuberosus (Menhaj et al 1999), BanLec from ripe bananas (M. acuminata L.; Peumans et al 2000), Orysata and OsJAC1 from O. sativa (Jiang et al 2006), Hfr-1 (Hessian Xy response; Williams et al 2002) and JRP-32 (jasmonateregulated proteins) from wheat (T. aestivum L.; Wang and Ma 2005), and Horcolin from barley (H. vulgare; Grunwald et al 2007). …”

Monocot chimeric jacalins: a novel subfamily of plant lectins

“…Horcolin is a 15 kDa mJRL specifically expressed in the coleoptile of barley (Grunwald et al, 2007), while a comprehensive genome analysis has revealed that dirigent genes are present in barley (HvDir; Matsumoto et al, 2011). A comparison of the protein structures showed the distribution of dirigent and JRL domains in Horcolin, HvDir, and HvJRP1 ( Figure 2).…”