Table 2.
Summary of Nitrosyl Geometry in Heme Proteins.17
| Complex | Fe—NNOa | ∠FeNOb | N—Oa | φb,c | φ*b,d |
|---|---|---|---|---|---|
| Iron(II) five-coordinate hemes | |||||
| [Fe(Deut)(NO)] | 1.723(3) | 143.1(3) | 1.187(4) | 35 | 35 |
| (T243N-P450nor)NO | 1.9e | 131e | 1.45e | 41 | −49 |
| (cyt c′)NO (1)f | 2.0 | 124 | 1.16e | 24 | −114 |
| (NP1)NO (I)g | NA | 125 | NA | 44 | 134 |
| (NP1)NO (II)h | NA | 135 | NA | 45 | 135 |
| (eNOS)NO(+4HB)i,j | 1.80 | 160 | 1.15 | 44 | 136 |
| (eNOS)NO(−4HB)i,k | 1.80 | 160 | 1.14 | 34 | 146 |
| (α-Hb)NO | 1.74 | 145 | 1.1 | 25 | 245 |
| (NP4)NO (I)l | 2.0 | 110 | NA | 1 | 269 |
| (T243A-P450nor)NO | 2.1e | 120e | 1.42e | 14 | −284 |
| (T243V-P450nor)NO | 2.0e | 119e | 1.36e | 16 | −286 |
| (cyt c′)NO (2)m | 2.0 | 132 | 1.17e | 38 | −322 |
| (α-T-HbA)NO | 1.74 | 150 | 1.13 | --- | --- |
| Iron(II) six-coordinate hemes | |||||
| (cd1-NIR(tp))NO | 2.0 | 131 | 1.3e | 30 | 120 |
| (SiRHP)NO | 1.76 | 125 | 1.17e | 40 | −140 |
| (hh-Mb)NO | 2.03 | 147 | 1.14 | ~10 | −190 |
| (sw-L29F-Mb)NO | 1.86e | 130 | 1.14e | 11 | −191 |
| (sw-Mb)NO | 1.89 | 112 | 1.15 | 25 | −205 |
| (α-SNO-nitrosylHbA)NO | 1.75 | 131 | 1.13 | 44 | −224 |
| (β-SNO-nitrosylHbA)NO | 1.74 | 123 | 1.11 | 34 | −236 |
| (β-Hb)NOn | 1.74 | 145 | 1.1 | 15 | 255 |
| (fungal-NOR)NO | 1.63 | 161 | 1.16 | 28 | −298 |
| (S286T-fungalNOR)NO | 1.65 | 162 | 1.13 | 29 | −299 |
| (S286V-fungalNOR)NO | 1.62 | 162 | 1.13 | 45 | −315 |
| (SHP)NO | 1.8 | 112 | 1.36e | 45 | 315 |
| (cd1-NIR(pa))NO | 1.8 | 135 | 1.15 | 26 | 334 |
| (lupin-LbII)NO | 1.72 | 147 | 1.355e | 2 | 358 |
| (β-T-HbA)NO | 1.74 | 155 | 1.12 | --- | --- |
| (CCP)NO(1)o | 1.82 | 135 | --- | --- | --- |
| (CCP)NO(2)p | 1.82 | 125 | --- | --- | --- |
| (hh-Mb)NOq | 1.76 | 150 | 1.12 | --- | ---- |
| (soybean-LbII)NOq | 1.77 | 147 | 1.12 | --- | --- |
Value in angstroms.
Value in degrees.
Dihedral angle between Fe—N—O plane and closest Fe—Np vector.
Signed torsion angle for the unit O—N—Fe—Np of pyrrole ring IV. Positive values refer to NO coordinated on the “top” of the porphyrin and represent a clockwise rotation about the N(NO)—Fe axis between the O—N—Fe and N—Fe—Np planes whilst negative values represent NO coordinated on the “bottom” and a counterclockwise rotation is required. Absolute φ* values of 270, 180 and 90º result in NO orientations coincident with the Fe—Np bonds of pyrrole rings I, II and III respectively.
Value not reported in original literature report. Taken from PDB coordinates.
Nitrosyl conformer 1.
2 molecules in asymmetric unit, molecule I.
2 molecules in asymmetric unit, molecule II.
Values reported are averaged for both subunits.
Cofactor tetrahydrobiopterin present.
Cofactor tetrahydrobiopterin absent.
2 orientations of NO observed, orientation I.
Nitrosyl conformer 2.
Differs from α-form by orientation of NO with respect to the heme and coordination number.
Disordered oxygen, position 1.
Disordered oxygen, position 2.
Structure determined by multiple scattering XAFS.