N-terminal domains of DELLA proteins are intrinsically unstructured in the absence of interaction with GID1/gibberellic acid receptors.
The plant growth-repressing DELLA proteins (DELLAs) are known to represent a convergence point in integration of multiple developmental and environmental signals in planta, one of which is hormone gibberellic acid (GA). Binding of the liganded GA receptor (GID1/GA) to the N-terminal domain of DELLAs is required for GA-induced degradation of DELLAs via the ubiquitin-proteasome pathway, thus derepressing plant growth. However, the conformational changes of DELLAs upon binding to GID1/GA, which are the key to understanding the precise mechanism of GID1/GA-mediated degradation of DELLAs, remain unclear. Using biophysical, biochemical, and bioinformatics approaches, we demonstrated for the first time that the unbound N-terminal domains of DELLAs are intrinsically unstructured proteins under physiological conditions. Within the intrinsically disordered N-terminal domain of DELLAs, we have identified several molecular recognition features, sequences known to undergo disorder-to-order transitions upon binding to interacting proteins in intrinsically unstructured proteins. In accordance with the molecular recognition feature analyses, we have observed the binding-induced folding of N-terminal domains of DELLAs upon interaction with AtGID1/GA. Our results also indicate that DELLA proteins can be divided into two subgroups in terms of their molecular compactness and their interactions with monoclonal antibodies.
Sun
Xiaolin
X
New Zealand Institute for Plant and Food Research, Private Bag 11 030, Palmerston North, New Zealand. Xiaolin.Sun@plantandfood.co.nz
Jones
William T
WT
Harvey
Dawn
D
Edwards
Patrick J B
PJ
Pascal
Steven M
SM
Kirk
Christopher
C
Considine
Thérèse
T
Sheerin
David J
DJ
Rakonjac
Jasna
J
Oldfield
Christopher J
CJ
Xue
Bin
B
Dunker
A Keith
AK
Uversky
Vladimir N
VN
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000737:chemistry; D017360:Arabidopsis / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005875:Gibberellins / Q000737:chemistry*; D008969:Molecular Sequence Data; D009154:Mutation; D010940:Plant Proteins / Q000378:metabolism*; D011485:Protein Binding; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D011956:Receptors, Cell Surface / Q000737:chemistry* / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction
D000911:Antibodies, Monoclonal; D029681:Arabidopsis Proteins; C512225:GID1a protein, Arabidopsis; D005875:Gibberellins; D010940:Plant Proteins; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; C007842:gibberellic acid