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|Title:||Coupling of helix E-F motion with the O-nitrito and 2-nitrovinyl coordination in myoglobin||Authors:||Ioannou, Androulla
|Issue Date:||1-Feb-2017||Publisher:||Elsevier B.V.||Source:||Biophysical Chemistry Volume 221, 1 February 2017, Pages 10-16||Abstract:||Myoglobin (Mb) is known to react slowly with nitirite to form the green pigment by NO2− cordination to the heme Fe in the O-binding nitrito (O1[sbnd]N[dbnd]O2) mode and to the heme 2-vinyl position. Nitrite is a powerful oxidizing agent and a biological reservoir for NO that has been implicated in a variety of aerobic biological systems. Accordingly, it is important to elucidate the nature and variety of NO2− reaction mechanisms with Mb. We have performed principal component analysis (PCA, or essential dynamics) on Molecular Dynamics trajectories of all Mb[sbnd]NO2 coordination states to resolve the most important motions in the protein at 298 K. We show that the coordination or removal of NO2− to/from the heme iron is associated mainly with a motion of helix E and the coordination of NO2− to the 2-vinyl is associated with a motion of helix F and a correlated motion of helices E-F. This latter correlated motion can be attributed to the interaction of Val68 and Ile107 with the 2-nitrovinyl moiety. The resonance Raman results show that coordination of NO2− to the 2-vinyl is increased at pH 6.0 demonstrating that the amide protons in the F helix are not protected from access of solvent water and the helix F motion allows solvent access to the 2-vinyl group, without affecting the coordination to the heme Fe.||URI:||http://ktisis.cut.ac.cy/handle/10488/9323||ISSN:||03014622||Rights:||© 2016 Elsevier B.V.|
|Appears in Collections:||Άρθρα/Articles|
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