Chlorophyll f synthesis by a super-rogue photosystem II complex
Certain cyanobacteria synthesize chlorophyll molecules (Chl d and Chl f ) that absorb in the far-red region of the solar spectrum, thereby extending the spectral range of photosynthetically active radiation 1 , 2 . The synthesis and introduction of these far-red chlorophylls into the photosynthetic...
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Veröffentlicht in: | Nature plants 2020-03, Vol.6 (3), p.238-244 |
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Zusammenfassung: | Certain cyanobacteria synthesize chlorophyll molecules (Chl
d
and Chl
f
) that absorb in the far-red region of the solar spectrum, thereby extending the spectral range of photosynthetically active radiation
1
,
2
. The synthesis and introduction of these far-red chlorophylls into the photosynthetic apparatus of plants might improve the efficiency of oxygenic photosynthesis, especially in far-red enriched environments, such as in the lower regions of the canopy
3
. Production of Chl
f
requires the ChlF subunit, also known as PsbA4 (ref.
4
) or super-rogue D1 (ref.
5
), a paralogue of the D1 subunit of photosystem II (PSII) which, together with D2, bind cofactors involved in the light-driven oxidation of water. Current ideas suggest that ChlF oxidizes Chl
a
to Chl
f
in a homodimeric ChlF reaction centre (RC) complex and represents a missing link in the evolution of the heterodimeric D1/D2 RC of PSII (refs.
4
,
6
). However, unambiguous biochemical support for this proposal is lacking. Here, we show that ChlF can substitute for D1 to form modified PSII complexes capable of producing Chl
f
. Remarkably, mutation of just two residues in D1 converts oxygen-evolving PSII into a Chl
f
synthase. Overall, we have identified a new class of PSII complex, which we term ‘super-rogue’ PSII, with an unexpected role in pigment biosynthesis rather than water oxidation.
The cyanobacterial chlorophyll, Chl
f
, absorbs far-red light. Mutation of two residues in a subunit of photosystem II converts it to a Chl
f
synthase. This ‘super-rogue’ photosystem might improve photosynthetic efficiency in low light. |
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ISSN: | 2055-0278 2055-0278 |
DOI: | 10.1038/s41477-020-0616-4 |