International
Tables for
Crystallography
Volume F
Crystallography of biological macromolecules
Edited by M. G. Rossmann and E. Arnold

International Tables for Crystallography (2006). Vol. F. ch. 23.2, p. 580

Table 23.2.3.1 

A. E. Hodela and F. A. Quiochob

aDepartment of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA, and  bHoward Hughes Medical Institute and Department of Biochemistry, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA

Table 23.2.3.1 | top | pdf |
Metal ions associated with proteins

Metal ion Concentration in blood plasma (mM) Common cofactors Hard/soft classification Common coordination number and geometry Preferred ligand atom
Na+ 138   Hard 6 O
K+ 4   Hard 8 O
Ca2+ 3   Hard 8 O
Mg2+ 1   Hard 6 O
Fe 0.02 Haem Intermediate 6 (octahedral) N
Zn2+ 0.02   Intermediate 4 (tetrahedral), 6 (octahedral) N, S
Cu2+ 0.015   Soft 4 (tetrahedral) S
Co2+ 0.002   Hard 6 (octahedral) O
Mn2+ 0   Hard 6 (octahedral) O
Ni2+ 0   Intermediate 6 (octahedral) N
Mo 0 Pterin Intermediate 6 (octahedral) S
W 0 Pterin Intermediate 6 (octahedral) S
V 0     5 (trigonal bipyramidal)