Toward modeling H-NOX domains: A DFT study of heme-NO complexes as hydrogen bond acceptors
Toward modeling H-NOX domains: A DFT study of heme-NO complexes as hydrogen bond acceptors
复制标题
DOI：
10.1021/ic050486q
复制
发表时间：
2005-10-31
影响因子：
4.6
通讯作者：
Ghosh, A
中科院分区：
文献类型：
--
作者：
Tangen, E;Svadberg, A;Ghosh, A
密度泛函理论计算用PW 91/STO-TZP（包括基组叠加误差修正）计算了5和6配位的血红素-NO与苯酚和咪唑的复合物的氢键能，苯酚和咪唑被选作远端口袋酪氨酸和组氨酸残基的模型，计算的相互作用能约为2kcal/mol，咪唑约为3- 4kcal/mol，其比血红素-O-2复合物与远端组氨酸的氢键所计算的能量小2-4倍。有趣的是，氢键能被发现是非常相似的五，六坐标血红素-NO复合物，这可能被视为相反的解释最近观察到的细菌H-NOX（血红素-一氧化氮/氧结合）蛋白质的序列同源性的大肠杆菌可溶性鸟苷酸环化酶。
Density functional theory calculations (PW91/STO-TZP, including basis-set superposition error corrections) have been used to evaluate hydrogen bond energies of five- and six-coordinate heme-NO complexes with phenol and imidazole, chosen as models for distal pocket tyrosine and histidine residues, The calculated interaction energies are approximately 2 kcal/mol for phenol and 3-4 kcal/mol for imidazole, which are 2-4 times smaller than the energies calculated for heme-O-2 complexes hydrogen-bonding with a distal histidine. Interestingly, the hydrogen bond energies are found to be very similar for five- and six-coordinate heme-NO complexes, which may be viewed as contrary to the interpretation of a recent observation on a bacterial H-NOX (Heme-Nitric oxide/OXygen-binding) protein with sequence homology to mammalian-soluble guanylate cyclase.