PMID- 21894911
OWN - NLM
STAT- MEDLINE
DCOM- 20120316
LR  - 20221207
IS  - 1520-510X (Electronic)
IS  - 0020-1669 (Linking)
VI  - 50
IP  - 19
DP  - 2011 Oct 3
TI  - Ligand binding intermediates of nitrosylated human hemoglobin induced at low 
      temperature by X-ray irradiation.
PG  - 9423-9
LID - 10.1021/ic201086u [doi]
AB  - Under prolonged X-ray irradiation, the ferrous heme of nitrosylated human adult 
      hemoglobin derivative (HbNO) undergoes a reversible transition generating a 
      5-coordinate species, due to release of the Fe-NO bond. The overall process can 
      be investigated using X-ray absorption near edge structure (XANES) spectroscopy. 
      In this work, Fe K-edge XANES spectra were measured at T < 15 K, pH 9.2, i.e., on 
      a high-affinity state (R-HbNO) where all the hemes are 6-coordinate, and at pH 
      6.5 in the presence of inositol hexakis-phosphate (IHP), i.e., on a low-affinity 
      ligated state (T-HbNO) where the iron-hemes of the alpha-chains are 5-coordinate due 
      to breaking of the Fe-proximal histidine bond. Under X-ray irradiation, 
      5-coordinate Fe-hemes are populated in both R-HbNO and T-HbNO, the Fe-NO bond 
      lysis induced in T-HbNO involving rebinding of the proximal histidine to the 
      transiently populated 4-coordinate hemes of the alpha-chains. A detailed analysis of 
      the spectra confirms that different intermediate states in the ligand binding 
      cooperative process of hemoglobin can be populated by X-ray irradiation, and that 
      the part of the energy associated to the R-T quaternary transition, that is 
      transmitted to the heme site, can be monitored by XANES spectroscopy.
FAU - Arcovito, Alessandro
AU  - Arcovito A
AD  - Istituto di Biochimica e Biochimica Clinica, Universita Cattolica del Sacro 
      Cuore, Largo F. Vito 1,00168, Roma, Italy. alessandro.arcovito@rm.unicatt.it
FAU - Della Longa, Stefano
AU  - Della Longa S
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20110830
PL  - United States
TA  - Inorg Chem
JT  - Inorganic chemistry
JID - 0366543
RN  - 0 (Glycated Hemoglobin A)
RN  - 0 (hemoglobin A, glycosylated-nitric oxide complex)
RN  - 31C4KY9ESH (Nitric Oxide)
RN  - E1UOL152H7 (Iron)
SB  - IM
MH  - Cold Temperature
MH  - Glycated Hemoglobin/*chemistry
MH  - Humans
MH  - Iron/*chemistry
MH  - Kinetics
MH  - Nitric Oxide/*chemistry
MH  - Protein Conformation
MH  - X-Ray Absorption Spectroscopy
EDAT- 2011/09/08 06:00
MHDA- 2012/03/17 06:00
CRDT- 2011/09/08 06:00
PHST- 2011/09/08 06:00 [entrez]
PHST- 2011/09/08 06:00 [pubmed]
PHST- 2012/03/17 06:00 [medline]
AID - 10.1021/ic201086u [doi]
PST - ppublish
SO  - Inorg Chem. 2011 Oct 3;50(19):9423-9. doi: 10.1021/ic201086u. Epub 2011 Aug 30.