2O66

Crystal Structure of Arabidopsis PII Reveals Novel Structural Elements Unique to Plants.

(2007) Biochemistry 46: 1477-1483

• PubMed: 17279613 Search on PubMed
• DOI: https://doi.org/10.1021/bi062149e
• Primary Citation of Related Structures:  
  2O66, 2O67


• PubMed Abstract: 
  

  The 1.9 A resolution crystal structure of PII from Arabidopsis thaliana reveals for the first time the molecular structure of a widely conserved regulator of carbon and nitrogen metabolism from a eukaryote. The structure provides a framework for understanding the arrangement of highly conserved residues shared with PII proteins from bacteria, archaea, and red algae as well as residues conserved only in plant PII. Most strikingly, a highly conserved segment at the N-terminus that is found only in plant PII forms numerous interactions with the alpha2 helix and projects from the surface of the homotrimer opposite to that occupied by the T-loop. In addition, solvent-exposed residues near the T-loop are highly conserved in plants but differ in prokaryotes. Several residues at the C-terminus that are also highly conserved only in plants contribute part of the ATP-binding site and likely participate in an ATP-induced conformational change. Structures of PII also reveal how citrate and malonate bind near the triphosphate binding site occupied by ATP in bacterial and archaeal PII proteins.

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Organizational Affiliation: 

Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada T2N 1N4.