A Three-Dimensional Protein Molecule (image) University of Bristol Share Print E-Mail Caption A three-dimensional protein molecule is projected into three perpendicular directions. The projection in each direction corresponds to a virtual knot, which looks like a diagram of an open-ended knot, whose termini are 'virtually closed.' Credit University of Bristol Usage Restrictions None Share Print E-Mail 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.