Three-dimensional structure of a new form of mare lactoferrin in 70% PEG 400 at 3.8 A resolution
Kumar, S.; Sharma, A.K.; Paramasivam, M.; Srinivasan, A.; Singh, T.P.
Indian Journal of Biochemistry and Biophysics 38(3): 135-141
2001
ISSN/ISBN: 0301-1208 PMID: 11693374 Document Number: 536119
Three-dimensional (3D) structure of a new form of diferric mare lactoferrin has been determined at 3.8 A resolution. The protein was crystallized in a space group P212121 with a = 80.1 A, b = 103.7 A, c = 112.2 A with a solvent content of 57%. The structure was solved by molecular replacement method using the model of native mare lactoferrin. The structure has been refined using X-PLOR to a final R-factor of 22.6% for all the data in 15.0-3.8 A resolution range. The final refined model comprises 5281 protein atoms, 2Fe3+ and 2CO32- ions. The protein folds into two globular N- and C-lobes. The two lobes are further divided into two domains N1, N2 in the N-lobe and C1, C2 in the C-lobe. The overall folding of the protein is similar to that observed for the native protein. The superposition of C alpha traces of native mare lactoferrin and the present structure gives an r.m.s shift of 0.7 A. There is a slight variation in the orientation of two lobes but the domain orientations in the present structure are identical to those observed in the native mare lactoferrin.