Résumé
The proteins which make the major contribution to wheat quality are known as gliadins and glutenins. But recently, low molecular weight cystein rich proteins (LMW-CRP) have also been considered important for some quality parameters. A large number of studies have underlined the importance of SH/SS exchange reactions in the technological quality of wheats. The CRP appear to be good candidates to be implied in these reactions. In addition, it has been shown recently that a new system, NADP-dependent Thioredoxin, reduces both storage proteins and LMW-CRP and then are able to react with other components. After describing the different known members of LMW-CRP, we present results obtained with two families of CRP: the CM-proteins and the Lipid Transfer Proteins. Several cDNAs clones encoding these proteins have been isolated. All these CRP are synthesized as precursors of larger molecular weight, the molecular mass of the mature proteins range from 7 to 16 kDa and they all contain 8 to 10 cystein residues. During seed development, the pattern of accumulation of mRNAs is specific for each ' family. In order to obtain a substantial amount of proteins for structural analysis (such as RMN or X-ray cristallography) and to study their structure-function relationships, we used two expression systems in E. coli. The perspectives of this work is both to have a better knowledge of the in vivo role of these proteins and to prepare th way to transgenic cereals with improved technological properties