Dear All, Thank you for your previous response. I have built a 3-mer oligosaccharides in the electron density by using coot. I prefer to refine my structure in CNS due the resolution is only 2.6 Ang. I found there are only topology and parameter files for carbohydrate in CNS but no linkage file for carbohydrate. So CNS could recognize the sugar molecules individually, but can not recognize the linkage between them. When I refine it in CNS, a oxygen will be added beyond C1 of NAG. Is there anyone who has the linkage file for carbohydrate of CNS? Or is there any other methods to deal with this situation?
Thanks.
