1nin
From Proteopedia
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PLASTOCYANIN FROM ANABAENA VARIABILIS, NMR, 20 STRUCTURES
Overview
The three-dimensional solution structure of plastocyanin from Anabaena, variabilis (A.v.PCu) has been determined by nuclear magnetic resonance, spectroscopy. Sixty structures were calculated by distance geometry from, 1141 distance restraints and 46 dihedral angle restraints. The distance, geometry structures were optimized by simulated annealing and restrained, energy minimization. The average rms deviation from the mean structure for, the 20 structures with the lowest total energy is 1.25 A for the backbone, atoms and 1.75 A for all heavy atoms. Overall, the global tertiary fold of, A.v.PCu resembles those of other plastocyanins which have been, structurally characterized by X-ray diffraction and NMR methods. This, holds even though A.v.PCu is longer than any other known plastocyanins, contains far less invariant amino acid residues, and has an overall charge, that differs considerably from those of other plastocyanins (+1 vs -9 +/-, 1 at pH > or = 7). The most striking feature of the A.v. PCu structure is, the absence of the beta-turn, formed at the remote site by residues, (58)-(61) in most higher plant plastocyanins. The displacement caused by, the absence of this turn is compensated for by an extension of the small, helix [from Ala53(51) to Ser60(58) in A.v.PCu] found in other, plastocyanins. Moreover, the extra residues of A.v.PCu from Pro77 to Asp79, form an appended loop. These two features allow A.v.PCu to retain almost, the same global fold as observed in other plastocyanins. From a comparison, with the structures of other plastocyanins it is concluded that the lack, of negatively charged residues at the remote site, rather than the, specific structure of A.v.PCu, is the main reason for the failure of the, remote site of this plastocyanin to function as a significant electron, transfer site.
About this Structure
1NIN is a Single protein structure of sequence from Anabaena variabilis with CU as ligand. Full crystallographic information is available from OCA.
Reference
Solution structure of reduced plastocyanin from the blue-green alga Anabaena variabilis., Badsberg U, Jorgensen AM, Gesmar H, Led JJ, Hammerstad JM, Jespersen LL, Ulstrup J, Biochemistry. 1996 Jun 4;35(22):7021-31. PMID:8679527
Page seeded by OCA on Tue Nov 20 22:17:48 2007
