Paramagnetic NMR study of Cu(2+)-IDA complex localization on a protein surface and its application to elucidate long distance information.
The paramagnetic metal chelate complex Cu(2+)-iminodiacetic acid (Cu(2+)-IDA) was mixed with ubiquitin, a small globular protein. Quantitative analyses of (1)H and (15)N chemical shift changes and line broadenings induced by the paramagnetic effects indicated that Cu(2+)-IDA was localized to a histidine residue (His68) on the ubiquitin surface. The distances between the backbone amide proton and the Cu(2+) relaxation center were evaluated from the proton transverse relaxation rates enhanced by the paramagnetic effect. These correlated well with the distances calculated from the crystal structure up to 20 A. Here, we show that a Cu(2+)-IDA is the first paramagnetic reagent that specifically localizes to a histidine residue on the protein surface and gives the long-range distance information.
Nomura
Makoto
M
Laboratory of Biophysics, Graduate School of Biological Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan.
Kobayashi
Toshitatsu
T
Kohno
Toshiyuki
T
Fujiwara
Kenichiro
K
Tenno
Takeshi
T
Shirakawa
Masahiro
M
Ishizaki
Itsuko
I
Yamamoto
Kazuo
K
Matsuyama
Toshifumi
T
Mishima
Masaki
M
Kojima
Chojiro
C
D000577:Amides / Q000737:chemistry; D000595:Amino Acid Sequence; D003300:Copper / Q000737:chemistry* / Q000378:metabolism; D006639:Histidine / Q000737:chemistry; D006801:Humans; D007098:Imino Acids / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D025801:Ubiquitin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
D000577:Amides; D007098:Imino Acids; D011994:Recombinant Proteins; D025801:Ubiquitin; D006639:Histidine; D003300:Copper; C008109:iminodiacetic acid