Cleavage after residue Ala352 in the C-terminal extension is an early step in the maturation of the D1 subunit of Photosystem II in Synechocystis PCC 6803
Language English Country Netherlands Media print-electronic
Document type Journal Article, Research Support, Non-U.S. Gov't
Grant support
BB/C507037/1
Biotechnology and Biological Sciences Research Council - United Kingdom
PubMed
17300742
DOI
10.1016/j.bbabio.2007.01.005
PII: S0005-2728(07)00008-4
Knihovny.cz E-resources
- MeSH
- Alanine chemistry MeSH
- Photosystem II Protein Complex chemistry genetics metabolism MeSH
- Mass Spectrometry MeSH
- Molecular Sequence Data MeSH
- Protein Subunits chemistry metabolism MeSH
- Proline metabolism MeSH
- Amino Acid Sequence MeSH
- Amino Acid Substitution MeSH
- Synechocystis genetics metabolism MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Alanine MeSH
- Photosystem II Protein Complex MeSH
- Protein Subunits MeSH
- Proline MeSH
We have investigated the pathway by which the 16 amino-acid C-terminal extension of the D1 subunit of photosystem two is removed in the cyanobacterium Synechocystis sp. PCC 6803 to leave Ala344 as the C-terminal residue. Previous work has suggested a two-step process involving formation of a processing intermediate of D1, termed iD1, of uncertain origin. Here we show by mass spectrometry that a synthetic peptide mimicking the C- terminus of the D1 precursor is cleaved by cellular extracts or purified CtpA processing protease after residue Ala352, making this a likely site for formation of iD1. Characteristics of D1 site-directed mutants with either the Leu353 residue replaced by Pro or with a truncation after Ala352 are in agreement with this assignment. Interestingly, analysis of various CtpA and CtpB null mutants further indicate that the CtpA protease plays a crucial role in forming iD1 but that, surprisingly, low levels of C-terminal processing occur in vivo in the absence of CtpA and CtpB, possibly catalysed by other related proteases. A possible role for two-step maturation of D1 in the assembly of PSII is discussed.
References provided by Crossref.org
The biogenesis and maintenance of PSII: Recent advances and current challenges
