title: NMR spectra and potentiometry studies of aluminum(III) binding with coenzyme NAD+ in acidic aqueous solutions.
abstract: Complexation and conformational studies of coenzyme NAD+ with aluminum were conducted in acidic aqueous solutions (pH 2-5) by means of potentiometry as well as multinuclear (1H, 13C, 31P, 27Al) and two-dimensional (1H, 1H-NOESY) NMR spectroscopy. These led to the following results: (1) Al could coordinate with NAD+ through the following binding sites: N7' of adenine and pyrophosphate free oxygen (O(A)1, O(N)1,O(A)2) to form various mononuclear 1:1 (AlLH23+, AlLH2+) and 2:1 (AlL2-) species, and dinuclear 2:2 (Al2L22+) species. (2) The conformations of NAD+ and Al-NAD+ depended on the solvents and different species in the complexes. The results suggest the occurrence of an Al-linked complexation, which causes structural changes at the primary recognition sites and secondary conformational alterations for coenzymes. This finding will help us to understand role of Al in biological enzyme reaction systems.
authors.affiliation: State Key Laboratory of Coordination Chemistry, Department of Chemistry, Nanjing University, Nanjing, 210093, P.R. China.
authors.forename: Xiaodi
authors.initials: X
authors.lastname: Yang
authors.forename: Shuping
authors.initials: S
authors.lastname: Bi
authors.forename: Xiaoliang
authors.initials: X
authors.lastname: Yang
authors.forename: Li
authors.initials: L
authors.lastname: Yang
authors.forename: Jun
authors.initials: J
authors.lastname: Hu
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
authors.forename: Zhengbiao
authors.initials: Z
authors.lastname: Yang
mesh_terms: D000535:Aluminum / Q000032:analysis / Q000378:metabolism*; D001665:Binding Sites; D018360:Crystallography, X-Ray; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D009243:NAD / Q000032:analysis / Q000378:metabolism*; D011199:Potentiometry; D011522:Protons; D012996:Solutions
chemical_list: D007202:Indicators and Reagents; D011522:Protons; D012996:Solutions; D009243:NAD; D000535:Aluminum