PDBsum entry 1psf

Photosystem i

PDB id: 1psf

Contents

Protein chain

69 a.a.

References listed in PDB file

Key reference

• Title: Three-Dimensional solution structure of psae from the cyanobacterium synechococcus sp. Strain pcc 7002, A photosystem i protein that shows structural homology with sh3 domains.
• Authors: C.J.Falzone, Y.H.Kao, J.Zhao, D.A.Bryant, J.T.Lecomte.
• Ref.: Biochemistry, 1994, 33, 6052-6062. [DOI no: 10.1021/bi00186a004]
• PubMed id: 8193119

Abstract

PsaE is a 69 amino acid polypeptide from photosystem I present on the stromal side of the thylakoid membrane. The three-dimensional solution structure of this protein from the cyanobacterium Synechococcus sp. strain PCC 7002 was determined at pH 5.8 and room temperature using over 900 experimental restraints derived from two- and three-dimensional NMR experiments. The structure is comprised of a well-defined five-stranded beta-sheet with (+1, +1, +1, -4 alpha) topology. There is no helical region except for a single turn of 3(10) helix between the beta D and beta E strands. PsaE also exhibits a large unrestrained loop spanning residues 42-56. A comparison to known protein structures revealed similarity with the Src homology 3 (SH3) domain, a membrane-associated protein involved in signal transduction in eukaryotes. The match is remarkable as 47 of the alpha-carbons of PsaE can be superimposed onto those of the SH3 domain from chicken brain alpha-spectrin with a root-mean-square deviation of 2.3 A. Although the amino acid sequences have low identity and the loops are different in both proteins, the topology of the beta-sheet and the 3(10) turn is conserved. SH3 domains from other sources show a similar structural homology. The structure of PsaE was used to suggest approaches for elucidating its roles within photosystem I.

Secondary reference #1

• Title: 1h and 15n nmr assignments of psae, A photosystem i subunit from the cyanobacterium synechococcus sp. Strain pcc 7002.
• Authors: C.J.Falzone, Y.H.Kao, J.Zhao, K.L.Maclaughlin, D.A.Bryant, J.T.Lecomte.
• Ref.: Biochemistry, 1994, 33, 6043-6051. [DOI no: 10.1021/bi00186a003]
• PubMed id: 8193118