A structural view of the conserved domain of rice stress-responsive NAC1

Abstract

The importance of NAC (named as NAM, ATAF1, 2, and CUC2) proteins in plant development, transcription regulation and regulatory pathways involving proteinprotein interactions has been increasingly recognized. We report here the high resolution crystal structure of SNAC1 (stress-responsive NAC) NAC domain at 2.5 Å. Although the structure of the SNAC1 NAC domain shares a structural similarity with the reported structure of the ANAC NAC1 domain, some key features, especially relating to two loop regions which potentially take the responsibility for DNA-binding, distinguish the SNAC1 NAC domain from other reported NAC structures. Moreover, the dimerization of the SNAC1 NAC domain is demonstrated by both soluble and crystalline conditions, suggesting this dimeric state should be conserved in this type of NAC family. Additionally, we discuss the possible NAC-DNA binding model according to the structure and reported biological evidences.

A STRESS-RESPONSIVE NAC1-Regulated Protein Phosphatase Gene RiceProtein Phosphatase18Modulates Drought and Oxidative Stress Tolerance through Abscisic Acid-Independent Reactive Oxygen Species Scavenging in Rice

“…Structure analysis of the SNAC1 NAC domain revealed structural similarities with the reported structure of the Arabidopsis ANAC NAC domain (Chen et al, 2011). To test whether SNAC1 can bind to the promoter of OsPP18, a genomic fragment of the OsPP18 promoter containing the CDBS located upstream of the start codon (Fig.…”

Detection of NAM-A1 Natural Variants in Bread Wheat Reveals Differences in Haplotype Distribution between a Worldwide Core Collection and European Elite Germplasm

“…Dimerization of DNA binding domains is common and can modulate the DNA-binding specificity [25]. Gel filtration studies on ANAC NAC domain [22] and SNAC1 NAC domain [21] have shown that in solution they exist as dimers that form the functional unit necessary for stable DNA binding [24]. We can reasonably presume that it is also the case for NAM-A1.…”

“…Prediction of the NAM-A1 NAC domain 3D structure was based on the crystal structure of the rice stress responsive NAC1 (SNAC1) NAC domain [21]. Crystallographic analysis of the NAC domain of the ANAC protein [22,23] encoded by the abscisic acid-responsive NAC gene from Arabidopsis thaliana and mutants study [24] were also used.…”

“…The NAM-A1 NAC domain prediction resulted in seven twisted β-strands forming a semi-β-barrel with four α-helices (Figure 1). Although the residues of the loop region between β6-β7 in both SNAC1 and ANAC NAC domains were unobserved due to its non-participation in crystal packing [21], in NAM-A1 NAC domain an α-helix is predicted. This α4-helix is truncated in the protein encoded by the haplotypes NAM-A1c and NAM-A1d, due to SNP1 alanine to valine substitution (Figure 1).…”

“…We can reasonably presume that it is also the case for NAM-A1. The interface between the two monomers of SNAC1 consists of residues in the N-terminal loop region and two residues in the α1-helix [21]. In NAM-A1, this domain is not predicted to be affected by SNP1 variation.…”