Abstract
As part of a large programme [Scottish Executive Rural Affairs Department Programme of Agricultural, Biological and Related Research: Exploitation of Novel and Known Lectins in Agricultural and Biological Research—an Interdisciplinary Approach to Improve Crop Protection and Productivity, Animal (Including Human) Welfare and Health (Project No. FF821). Scottish Executive Rural Affairs Department (http://www.scotland.gov.uk/abrg/docs/pabr-00.asp)] concerned with the discovery and development of new and existing plant lectins, a screening exercise for novel mannose binding lectins (MBLs) was initiated. Common agricultural and horticultural crops were screened and of the 50 species initially screened, 15 were shown to be putative sources of MBLs. Following isolation by mannose-affinity and phenyl-Sepharose™ chromatographies the proteins were characterised with regard to their structure and functionality. The species within the Amaryllidacea and Liliaceae had the MBLs present at the greatest levels (=6000 µg [g fresh wt.]-1). The novel MBLs were present at relatively low levels (15–60 µg [g fresh wt.]-1). All the MBLs exhibited monomer molecular weights in the range 11–13 kD whilst the native molecular weights were indicative of dimer or tetramer formation.
The linkage preferences of the MBLs were determined by inhibiting the MBL-yeast mannan precipitation reaction by the addition of oligomannans with defined linkages. The preference for a(1–3) and a(1–6) linkages was predominant throughout the known and novel MBLs. Evidence of binding to a(1–2) and a(1–4) linked ligands was seen but the relative affinity for these was low with the exception of the MBL from leafbeet (Beta vulgaris ssp. cicla). The MBL from celeriac (Apium graveolens) did bind ß-linked ligands but this was most probably due to a lack of specificity rather than a different specificity. Overall the relative binding affinity of the MBLs increased with increasing complexity of the ligands.
© 2004 Elsevier
The linkage preferences of the MBLs were determined by inhibiting the MBL-yeast mannan precipitation reaction by the addition of oligomannans with defined linkages. The preference for a(1–3) and a(1–6) linkages was predominant throughout the known and novel MBLs. Evidence of binding to a(1–2) and a(1–4) linked ligands was seen but the relative affinity for these was low with the exception of the MBL from leafbeet (Beta vulgaris ssp. cicla). The MBL from celeriac (Apium graveolens) did bind ß-linked ligands but this was most probably due to a lack of specificity rather than a different specificity. Overall the relative binding affinity of the MBLs increased with increasing complexity of the ligands.
© 2004 Elsevier
Original language | English |
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Pages (from-to) | 137-146 |
Number of pages | 10 |
Journal | Industrial Crops and Products |
Volume | 19 |
DOIs | |
Publication status | Published - Mar 2004 |
Keywords
- mannose-binding lectin
- plant
- specificity
- affinity