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Refined crystal structure of ytterbium‐substituted carp parvalbumin 4.25 at 1.5 Å, and its comparison with the native and cadmium‐substituted structures
Author(s) -
Kumar Vinod D.,
Lee Lana,
Edwards Brian F.P.
Publication year - 1991
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(91)80616-b
Subject(s) - ytterbium , cadmium , parvalbumin , chemistry , crystal structure , crystallography , materials science , biology , organic chemistry , doping , optoelectronics , genetics
The crystal structure of carp parvalbumin 4.25 containing a 1:1 molar ratio of ytterbium chloride to protein has been refined at 1.5 Å resolution by restrained least‐squares methods to a crystallographic R value of 0.199. The crystal structure confirms the NMR studies, which suggest that low concentrations of ytterbium cause an extensive displacement of calcium from the EF metal binding site. A comparison of the ytterbium‐substituted model with the native and cadmium‐substituted structure show no significant differences, except around the substituted EF metal‐binding region. The displacement of calcium by ytterbium at the EF site has caused a movement in the polypeptide backbone of Ser‐91 and Asp‐92. This movement resulted in an increase in the number of oxygen ligands bound to ytterbium in the EF site from seven to eight.