Figure 2. Distance in Å between the conserved E of CSRIV (blue) and catalytic residues E in CSR III and D in CSR IV (red). A. GH57 4-α-glucanotransferase of Thermococcus litoralis ; B. GH57 AmyC ofThermotoga maritima ; C. GH57 Glycogen branching enzyme ofThermus thermophilus .