Partial degradation of the 18-kDa protein of the photosynthetic oxygen-evolving complex: A study of a binding site

Tomohiko Kuwabara, Teruyo Murata, Mitsue Miyao, Norio Murata

Research output: Contribution to journalArticlepeer-review

63 Citations (Scopus)

Abstract

When the NaCl extract from spinach Photosystem II particles was dialyzed against a low-salt medium, the 18-kDa protein slowly degraded to a fragment of 17 kDa. This observation suggests that a proteinase previously associated with the Photosystem II particles in a latent form was activated by dissociation with NaCl. The 18-kDa protein and the 17-kDa fragment were purified, and their N-terminal amino acid sequences and total amino acid compositions were determined. These results determined 44 amino acid residues at the N-terminal of the 18-kDa protein, and suggest that 12 amino acid residues (mostly hydrophobic) at the N-terminal were lost by the degradation. The 18-kDa protein could rebind to the NaCl-treated and 24-kDa protein-supplemented Photosystem II particles and sustain their oxygen-evolution activity in a low-Cl- medium, whereas the 17-kDa fragment had lost these abilities. These observations suggest that the N-terminal region of the 18-kDa protein forms a domain which binds to Photosystem II particles.

Original languageEnglish
Pages (from-to)146-155
Number of pages10
JournalBBA - Bioenergetics
Volume850
Issue number1
DOIs
Publication statusPublished - 1986 Jun 10
Externally publishedYes

Keywords

  • (Spinach)
  • Chloride effect
  • Oxygen evolution
  • Proteinase
  • Thylakoid protein

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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