Crystal Structure of PCO4 (IMAGE) University of Sydney Caption Crystal structure of PCO4, highlighting key amino acid residues, the importance of which were verified in the model plant Arabidopsis. (WT = wild type, ie: plant in wild). Credit University of Oxford/PNAS Usage Restrictions for this story only License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.