Full backbone assignment and dynamics of the intrinsically disordered dehydrin ERD14.

Dehydrins are a class of stress proteins that belong to the family of Late Embryogenesis Abundant (LEA) proteins in plants, so named because they are highly expressed in late stages of seed formation. In somatic cells, their expression is very low under normal conditions, but increases critically upon dehydration elicited by water stress, high salinity or cold. Dehydrins are thought to be intrinsically disordered proteins, which represents a challenge in understanding their structure-function relationship. Herein we present the backbone (1)H, (15)N and (13)C NMR assignment of the 185 amino acid long ERD14 (Early Response to Dehydration 14), which is a K(3)S-type, typical dehydrin of A. thaliana. Secondary chemical shifts as well as NMR relaxation data show that ERD14 is fully disordered under near native conditions, with short regions of somewhat restricted motion and 5-25% helical propensity. These results suggest that ERD14 may have partially preformed elements for functional interaction with its partner(s) and set the stage for further detailed structural and functional studies of ERD14 both in vitro and in vivo.