Try refining your model both ways (with and without covalent link) and see if electron density maps give you an indication. At this resolution there will be some model bias, so be critical.
Sent on a Sprint Samsung Galaxy S® III <div>-------- Original message --------</div><div>From: rohit kumar <rohit...@gmail.com> </div><div>Date:08/19/2014 2:56 AM (GMT-05:00) </div><div>To: CCP4BB@JISCMAIL.AC.UK </div><div>Subject: [ccp4bb] </div><div> </div>Dear All, i have solved a structure of 3.2 A. That is a PLP depended enzyme. In their resting state, PLP-dependent enzymes are usually joined by a covalent aldimine linkage to an essential lysine residue with a C=N bond. This generates the so-called internal aldimine moiety. Could anybody tell me how we can say that this PLP is covalently attached to the Lys or its making Schiff base or not. -- WITH REGARDS Rohit Kumar Singh Lab. no. 430, P.I. Dr. S. Gourinath, School of Life Sciences, Jawaharlal Nehru University New Delhi -110067