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Cytokinin‐induced structural adaptability of a Lupinus luteus PR‐10 protein
Author(s) -
Fernandes Humberto,
Bujacz Anna,
Bujacz Grzegorz,
Jelen Filip,
Jasinski Michal,
Kachlicki Piotr,
Otlewski Jacek,
Sikorski Michal M.,
Jaskolski Mariusz
Publication year - 2009
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2009.06892.x
Subject(s) - cytokinin , biology , biochemistry , ligand (biochemistry) , chemistry , receptor , gene , auxin
Plant pathogenesis‐related (PR) proteins of class 10 are the only group among the 17 PR protein families that are intracellular and cytosolic. Sequence conservation and the wide distribution of PR‐10 proteins throughout the plant kingdom are an indication of an indispensable function in plants, but their true biological role remains obscure. Crystal and solution structures for several homologues have shown a similar overall fold with a vast internal cavity which, together with structural similarities to the steroidogenic acute regulatory protein‐related lipid transfer domain and cytokinin‐specific binding proteins, strongly indicate a ligand‐binding role for the PR‐10 proteins. This article describes the structure of a complex between a classic PR‐10 protein [ Lupinus luteus (yellow lupine) PR‐10 protein of subclass 2, LlPR‐10.2B] and N , N′ ‐diphenylurea, a synthetic cytokinin. Synthetic cytokinins have been shown in various bioassays to exhibit activity similar to that of natural cytokinins. The present 1.95 Å resolution crystallographic model reveals four N , N′ ‐diphenylurea molecules in the hydrophobic cavity of the protein and a degree of conformational changes accompanying ligand binding. The structural adaptability of LlPR‐10.2B and its ability to bind different cytokinins suggest that this protein, and perhaps other PR‐10 proteins as well, can act as a reservoir of cytokinin molecules in the aqueous environment of a plant cell.