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Structure-function relationship of pectins and pectolytic enzymes

Objective



Europe has a dominating role in industrial production of pectins and pectolytic enzymes. The major pectin suppliers are EU-based companies. Where present pectin technology uses inorganic acids and bases for extraction, purification and hydrolytic modification, the use of specific and pure enzymes for these purposes promises: Better control of functional properties of pectin in existing applications, and widening of the functional properties of pectins and thereby the fields of applications. Thereby, and through the growing preference for pectin as a functional food ingredient with positive nutritional effects, it is expected, that the growth in pectin consumption will increase. To realise the full effect of these prospects it is necessary to further strengthen the fundamental research into the molecular structure of pectin, and into existing and new pectolytic enzymes and their effect on pectins. Therefore, 6 EU-based scientific centers and an EU-based manufacturer of pectins and pectolytic enzymes have jointly drafted the present research proposal.
The first objective of this proposal is to develop new and better qualitative and quantitative methods to determine the structure of pectins from apple, citrus and other suitable plant materials, using the latest developments in analytical techniques and apparatus. Two complementary strategies will be followed: i) Enzymatic fingerprinting through use of a range of pure pectolytic enzymes. The pectin polymers will be degraded and the resulting fragments separated by HPLC followed by analysis on NMR, MS and Laser-Desorption MS in order to generate fingerprints correlating to specific pectin structures. ii) Development of Anti-pectin antibodies: The antibodies will be used to characterize the pectin- polymer with respect to substitution, e.g. methylation, amidation, free galacturonic acid residues as well as neutral sugar side chains.
The second objective is to study two specific pectolytic enzymes, Polygalacturonase and Pectin Lyase, and their interaction with pectic substrates. These enzymes were selected for the study as they can potentially be used to control two very important characteristics of pectin: Calcium sensitivity and Molecular weight. The study involves 3D-structural analysis of the enzymes and generation of new mutant enzymes by site directed mutagenesis. The structure-function relationship of the enzymes and specific tailor made substrates will be examined in details, using e.g. Surface Plasmon Resonance analysis. Interactions of the key enzymes with specific inhibitors (proteins) will also be addressed.
The third objective is to utilise the new basic knowledge to make new pectins and correlate the structural information with basic functional properties, e.g. rheologic properties and Calcium sensitivity.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Danisco A/S
Address
1,Langebrogade 1
1001 København
Denmark

Participants (5)

BBSRC Institute of Food Research
United Kingdom
Address
Reading Laboratory Earley Gate Whiteknights Road
RG6 2EF Reading
Institut National de la Recherche Agronomique
France
Address
Rue De La Géraudière
44316 Nantes
Landbouwuniversiteit Wageningen
Netherlands
Address
78,Biotechnion
6700 EV Wageningen
UNIVERSITY OF LEEDS
United Kingdom
Address
Woodhouse Lane
LS2 9JT Leeds
UNIVERSITY OF ROME "LA SAPIENZA"
Italy
Address
2,Piazzale Aldo Moro 5
00185 Roma