skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: A conserved proline residue in the leucine zipper region of AtbZIP34 and AtbZIP61 in Arabidopsis thaliana interferes with the formation of homodimer

Abstract

Two putative Arabidopsis E group bZIP transcript factors, AtbZIP34 and AtbZIP61, are nuclear-localized and their transcriptional activation domain is in their N-terminal region. By searching GenBank, we found other eight plant homologues of AtbZIP34 and AtbZIP61. All of them have a proline residue in the third heptad of zipper region. Yeast two-hybrid assay and EMSA showed that AtbZIP34 and AtbZIP61 could not form homodimer while their mutant forms, AtbZIP34m and AtbZIP61m, which the proline residue was replaced by an alanine residue in the zipper region, could form homodimer and bind G-box element. These results suggest that the conserved proline residue interferes with the homodimer formation. However, both AtbZIP34 and AtbZIP61 could form heterodimers with members of I group and S group transcription factors in which some members involved in vascular development. So we speculate that AtbZIP34 and AtbZIP61 may participate in plant development via interacting with other group bZIP transcription factors.

Authors:
 [1];  [2];  [3];  [1];  [4]
  1. College of Life Sciences, Beijing Normal University, Beijing 100875 (China)
  2. (China)
  3. State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200433 (China)
  4. (China), E-mail: xipingwang@hotmail.com
Publication Date:
OSTI Identifier:
21032934
Resource Type:
Journal Article
Resource Relation:
Journal Name: Biochemical and Biophysical Research Communications; Journal Volume: 362; Journal Issue: 2; Other Information: DOI: 10.1016/j.bbrc.2007.08.026; PII: S0006-291X(07)01687-7; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; ALANINES; ARABIDOPSIS; HYBRIDIZATION; LEUCINE; MUTANTS; PROLINE; TRANSCRIPTION FACTORS; YEASTS

Citation Formats

Shen Huaishun, State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200433, Cao Kaiming, Wang Xiping, and State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200433. A conserved proline residue in the leucine zipper region of AtbZIP34 and AtbZIP61 in Arabidopsis thaliana interferes with the formation of homodimer. United States: N. p., 2007. Web. doi:10.1016/j.bbrc.2007.08.026.
Shen Huaishun, State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200433, Cao Kaiming, Wang Xiping, & State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200433. A conserved proline residue in the leucine zipper region of AtbZIP34 and AtbZIP61 in Arabidopsis thaliana interferes with the formation of homodimer. United States. doi:10.1016/j.bbrc.2007.08.026.
Shen Huaishun, State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200433, Cao Kaiming, Wang Xiping, and State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200433. 2007. "A conserved proline residue in the leucine zipper region of AtbZIP34 and AtbZIP61 in Arabidopsis thaliana interferes with the formation of homodimer". United States. doi:10.1016/j.bbrc.2007.08.026.
@article{osti_21032934,
title = {A conserved proline residue in the leucine zipper region of AtbZIP34 and AtbZIP61 in Arabidopsis thaliana interferes with the formation of homodimer},
author = {Shen Huaishun and State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200433 and Cao Kaiming and Wang Xiping and State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200433},
abstractNote = {Two putative Arabidopsis E group bZIP transcript factors, AtbZIP34 and AtbZIP61, are nuclear-localized and their transcriptional activation domain is in their N-terminal region. By searching GenBank, we found other eight plant homologues of AtbZIP34 and AtbZIP61. All of them have a proline residue in the third heptad of zipper region. Yeast two-hybrid assay and EMSA showed that AtbZIP34 and AtbZIP61 could not form homodimer while their mutant forms, AtbZIP34m and AtbZIP61m, which the proline residue was replaced by an alanine residue in the zipper region, could form homodimer and bind G-box element. These results suggest that the conserved proline residue interferes with the homodimer formation. However, both AtbZIP34 and AtbZIP61 could form heterodimers with members of I group and S group transcription factors in which some members involved in vascular development. So we speculate that AtbZIP34 and AtbZIP61 may participate in plant development via interacting with other group bZIP transcription factors.},
doi = {10.1016/j.bbrc.2007.08.026},
journal = {Biochemical and Biophysical Research Communications},
number = 2,
volume = 362,
place = {United States},
year = 2007,
month =
}
  • Proline dehydrogenase (PRODH) catalyzes the oxidation of L-proline to {Delta}-1-pyrroline-5-carboxylate. PRODHs exhibit a pronounced preference for proline over hydroxyproline (trans-4-hydroxy-L-proline) as the substrate, but the basis for specificity is unknown. The goal of this study, therefore, is to gain insight into the structural determinants of substrate specificity of this class of enzyme, with a focus on understanding how PRODHs discriminate between the two closely related molecules, proline and hydroxyproline. Two site-directed mutants of the PRODH domain of Escherichia coli PutA were created: Y540A and Y540S. Kinetics measurements were performed with both mutants. Crystal structures of Y540S complexed with hydroxyproline, proline,more » and the proline analogue L-tetrahydro-2-furoic acid were determined at resolutions of 1.75, 1.90, and 1.85 {angstrom}, respectively. Mutation of Tyr540 increases the catalytic efficiency for hydroxyproline 3-fold and decreases the specificity for proline by factors of 20 (Y540S) and 50 (Y540A). The structures show that removal of the large phenol side chain increases the volume of the substrate-binding pocket, allowing sufficient room for the 4-hydroxyl of hydroxyproline. Furthermore, the introduced serine residue participates in recognition of hydroxyproline by forming a hydrogen bond with the 4-hydroxyl. This result has implications for understanding the substrate specificity of the related enzyme human hydroxyproline dehydrogenase, which has serine in place of tyrosine at this key active site position. The kinetic and structural results suggest that Tyr540 is an important determinant of specificity. Structurally, it serves as a negative filter for hydroxyproline by clashing with the 4-hydroxyl group of this potential substrate.« less
  • Plant disease resistance genes function in highly specific pathogen recognition pathways. RPS2 is a resistance gene of Arabidposis thaliana that confers resistance against Pseudomonas syringae bacteria that express avirulence gene avrRpt2. RPS2 was isolated by the use of a positional cloning strategy. The derived amino acid sequence of RPS2 contains leucine-rich repeat, membrane-spanning, leucine zipper, and P loop domains. The function of the RPS2 gene product in defense signal transduction is postulated to involve nucleotide triphosphate binding and protein-protein interactions and may also involve the reception of an elicitor produced by the avirulent pathogen.
  • The methionine chain-elongation pathway is required for aliphatic glucosinolate biosynthesis in plants and evolved from leucine biosynthesis. In Arabidopsis thaliana, three 3-isopropylmalate dehydrogenases (AtIPMDHs) play key roles in methionine chain-elongation for the synthesis of aliphatic glucosinolates (e.g. AtIPMDH1) and leucine (e.g. AtIPMDH2 and AtIPMDH3). Here we elucidate the molecular basis underlying the metabolic specialization of these enzymes. The 2.25 {angstrom} resolution crystal structure of AtIPMDH2 was solved to provide the first detailed molecular architecture of a plant IPMDH. Modeling of 3-isopropylmalate binding in the AtIPMDH2 active site and sequence comparisons of prokaryotic and eukaryotic IPMDH suggest that substitution of onemore » active site residue may lead to altered substrate specificity and metabolic function. Site-directed mutagenesis of Phe-137 to a leucine in AtIPMDH1 (AtIPMDH1-F137L) reduced activity toward 3-(2'-methylthio)ethylmalate by 200-fold, but enhanced catalytic efficiency with 3-isopropylmalate to levels observed with AtIPMDH2 and AtIPMDH3. Conversely, the AtIPMDH2-L134F and AtIPMDH3-L133F mutants enhanced catalytic efficiency with 3-(2'-methylthio)ethylmalate {approx}100-fold and reduced activity for 3-isopropylmalate. Furthermore, the altered in vivo glucosinolate profile of an Arabidopsis ipmdh1 T-DNA knock-out mutant could be restored to wild-type levels by constructs expressing AtIPMDH1, AtIPMDH2-L134F, or AtIPMDH3-L133F, but not by AtIPMDH1-F137L. These results indicate that a single amino acid substitution results in functional divergence of IPMDH in planta to affect substrate specificity and contributes to the evolution of specialized glucosinolate biosynthesis from the ancestral leucine pathway.« less