R.O. gratefully acknowledges receipt of a JSPS Postdoctoral Fellowship for Research Abroad. Use of NE-CAT beamline 24-ID at the Advanced Photon Source is supported by award RR-15301 from the National Center for Research Resources at the National Institutes of Health. Use of the Advanced Photon Source is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under contract no. DE-AC02-06CH11357.
(Quasi-)Racemic X-ray Structures of Glycosylated and Non-Glycosylated Forms of the Chemokine Ser-CCL1 Prepared by Total Chemical Synthesis†
Article first published online: 1 APR 2014
© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Volume 126, Issue 20, pages 5294–5298, May 12, 2014
How to Cite
Okamoto, R., Mandal, K., Sawaya, M. R., Kajihara, Y., Yeates, T. O. and Kent, S. B. H. (2014), (Quasi-)Racemic X-ray Structures of Glycosylated and Non-Glycosylated Forms of the Chemokine Ser-CCL1 Prepared by Total Chemical Synthesis. Angew. Chem., 126: 5294–5298. doi: 10.1002/ange.201400679
- Issue published online: 8 MAY 2014
- Article first published online: 1 APR 2014
- Manuscript Received: 21 JAN 2014
- Chemische Proteinsynthese;
- Quasiracemische Kristalle;
Our goal was to obtain the X-ray crystal structure of the glycosylated chemokine Ser-CCL1. Glycoproteins can be hard to crystallize because of the heterogeneity of the oligosaccharide (glycan) moiety. We used glycosylated Ser-CCL1 that had been prepared by total chemical synthesis as a homogeneous compound containing an N-linked asialo biantennary nonasaccharide glycan moiety of defined covalent structure. Facile crystal formation occurred from a quasi-racemic mixture consisting of glycosylated L-protein and non-glycosylated-D-protein, while no crystals were obtained from the glycosylated L-protein alone. The structure was solved at a resolution of 2.6–2.1 Å. However, the glycan moiety was disordered: only the N-linked GlcNAc sugar was well-defined in the electron density map. A racemic mixture of the protein enantiomers L-Ser-CCL1 and D-Ser-CCL1 was also crystallized, and the structure of the true racemate was solved at a resolution of 2.7–2.15 Å. Superimposition of the structures of the protein moieties of L-Ser-CCL1 and glycosylated-L-Ser-CCL1 revealed there was no significant alteration of the protein structure by N-glycosylation.