. Author manuscript; available in PMC: 2014 Mar 26.

Published in final edited form as: Biochemistry. 2013 Mar 15;52(12):10.1021/bi301620x. doi: 10.1021/bi301620x

Table 2.

Projections of heme planes in R state HbII crystals.

Subunit^a	sin²z_ia^b	sin²z_ib^b	sin²z_ic^b
deoxyHbII
A	0.0300	0.9808	0.9892
B	0.5028	0.9362	0.5611
C	0.9865	0.8240	0.1895
D	0.4941	0.6290	0.8769
E	0.9973	0.8237	0.1790
F	0.5463	0.6164	0.8373
G	0.0167	0.9841	0.9993
H	0.5762	0.9443	0.4794
HbII CO
A	0.9770	0.7795	0.2435
B	0.4858	0.6256	0.8886
C	0.0443	0.9845	0.9712
D	0.5684	0.9612	0.4704
E	0.9860	0.8108	0.2031
F	0.4467	0.6555	0.8978
G	0.0496	0.9765	0.9739
H	0.6079	0.9496	0.4425

Subunits A, C, E and G are “A” chains and subunits B, D, F and H are “B” chains.

z_ia, z_ib and z_ic are the angles between the normal to the plane of the heme cromophore (taken as the z molecular axis) and the a, b and c crystal axes. The plane of each heme cromophore was calculated using the 24 heme ring atoms (carbons and nitrogens). All normal vectors are chosen for simplicity so that the first component is positive; each normal vector is just the normalized eigenvector corresponding to the smallest eigenvalue of the moment-of-inertia tensor for that heme.

The fractional projections of the A hemes onto the a and c crystal axes, and therefore their fractional contribution to absorption measured along the two axes, are 0.489 and 0.461 for deoxyHbII, and 0.494 and 0.470 for HbII CO, respectively.