Affordable Access

Publisher Website

Paramagnetic ion binding to amino acids : the structure of the manganese (II)-L-proline complex from carbon-13 relaxation data

Authors
Journal
Advances in Molecular Relaxation and Interaction Processes
0378-4487
Publisher
Elsevier
Publication Date
Volume
16
Issue
1
Identifiers
DOI: 10.1016/0378-4487(80)80004-5
Disciplines
  • Mathematics

Abstract

Abstract Carbon-13 longitudinal relaxation times T 1 of aqueous solutions of proline at pH=11 containing 10 −4–10 −5M manganese(II) perchlorate are measured at 62.86 MHz and 60°C. Under these conditions, the Mn 2+ cation is bound to three proline molecules in their dibasic form to form the complex [Mn(L-PRO −) 3] −. The relaxation of carbons α, β, γ, δ in this complex is shown to be dipolar. The relevant correlation time is rotational τ r=4.3×10 −11s (at 60°C). A method is given to compute the Mn 2+- 13C distances in the complex from the paramagnetic relaxation rates 1/T 1M of carbons α to δ and an assumed geometry of the proline molecule. The manganese (II) cation may be positioned with respect to each proline ligand, thus determining the structure of the hexacoordinated complex. The sites of coordination are the uncharged nitrogen and one carboxylic oxygen atom of the proline molecules, their distance to the Mn 2+ cation are respectively 2.22 and 1.97 å.

There are no comments yet on this publication. Be the first to share your thoughts.