BROWSE

Related Researcher

Author's Photo

Cho, Moo Je
Ulsan National Institute of Science and Technology
Research Interests
  • Calcium Signaling
  • Calmodulin
  • Plant Defense Mechanism

ITEM VIEW & DOWNLOAD

Biochemical characteristics of a rice (Oryza sativa L, IR36) G-protein alpha-subunit expressed in Escherichia coli

Cited 20 times inthomson ciCited 20 times inthomson ci
Title
Biochemical characteristics of a rice (Oryza sativa L, IR36) G-protein alpha-subunit expressed in Escherichia coli
Author
Seo, HSChoi, CHLee, SYCho, Moo JeBahk, JD
Issue Date
1997-05
Publisher
PORTLAND PRESS LTD
Citation
BIOCHEMICAL JOURNAL, v.324, pp.273 - 281
Abstract
A cDNA encoding the alpha-subunit of the heterotrimeric G-protein in rice (RGA1) was overexpressed in Escherichia coli and then isolated by Ni2+-nitrilotriacetic acid affinity chromatography. The molecular mass of RGA1 bearing a His tag was approx. 49 kDa. Immunoblot analysis using anti-RGA1 revealed that the RGA1 protein is most abundant in seedling leaves and least abundant in mature roots. It exists at particularly high levels in the immature embryo after pellicle extrusion. In addition, the RGA1 antiserum exhibited a difference in binding affinity for G alpha proteins from monocots (maize and rice) and dicots (Arabidopsis, pea, soya bean and tomato); whereas it cross-reacted with G alpha proteins of monocots, it did not with those of dicot plants. When bound to guanosine 5'-(gamma-thio)triphosphate (GTP[S]), the RGA1 protein was partially protected from tryptic proteolysis. In the presence of GTP[S], trypsin cleaved the RGA1 protein into four fragments 24, 14, 11 and 5 kDa in size. When RGA1 was bound to GDP, only the 5 kDa polypeptide was seen on SDS/PAGE after trypsin digestion. Photoaffinity labelling with [alpha-P-32]GTP and a GTP[S]-binding assay revealed that RGA1 incorporated P-32 and showed specific binding to a guanine nucleotide. Guanidine binding of RGA1 was affected by the concentration of MgCl2 (maximum at 2 mM). The rate of guanine nucleotide binding of RGA1 (k(on,GTP(S))=0.0141+/-0.0014 min(-1)) and, at steady state, the k(cat) value for GTP hydrolysis (0.0075+/-0.0001 min(-1)) were very low even at 2 mM MgCl2. The binding affinity for the nucleotides examined was in the order GTP[S] greater than or equal to GTP > GDP > CTP > ATP greater than or equal to dTTP.
URI
https://scholarworks.unist.ac.kr/handle/201301/6320
URL
http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=0030916792
ISSN
0264-6021
Appears in Collections:
BIO_Journal Papers
Files in This Item:
There are no files associated with this item.

find_unist can give you direct access to the published full text of this article. (UNISTARs only)

Show full item record

qrcode

  • mendeley

    citeulike

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

MENU