Co-ordination of NDH and Cup proteins in CO₂ uptake in cyanobacterium Synechocystis sp. PCC 6803

High and low affinity CO₂-uptake systems containing CupA (NDH-1MS) and CupB (NDH-1MS′), respectively, have been identified in Synechocystis sp. PCC 6803, but it is yet unknown how the complexes function in CO₂ uptake. In this work, we found that deletion of cupB significantly lowered the growth of c...

Full description

Saved in:
Bibliographic Details
Published in:Journal of experimental botany 2017-06, Vol.68 (14), p.3869-3877
Main Authors: Han, Xunling, Sun, Nan, Xu, Min, Mi, Hualing
Format: Article
Language:English
Subjects:
Bacterial Proteins - genetics
Bacterial Proteins - metabolism
Biological Transport
Carbon Dioxide - metabolism
Photosynthesis
RESEARCH PAPER
Research Papers
Reverse Genetics
Sequence Deletion
Synechocystis - genetics
Synechocystis - metabolism
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:High and low affinity CO₂-uptake systems containing CupA (NDH-1MS) and CupB (NDH-1MS′), respectively, have been identified in Synechocystis sp. PCC 6803, but it is yet unknown how the complexes function in CO₂ uptake. In this work, we found that deletion of cupB significantly lowered the growth of cells, and deletion of both cupA and cupB seriously suppressed the growth below pH 7.0 even under 3% CO₂. The rate of photosynthetic oxygen evolution was decreased slightly by deletion of cupA but significantly by deletion of cupB and more severely by deletion of both cupA and cupB, especially in response to changed pH conditions under 3% CO₂. Furthermore, we found that assembly of CupB into NDH-1MS′ was dependent on NdhD4 and NdhF4. NDH-1MS′ was not affected in the NDH-1MS-degradation mutant and NDH-1MS was not affected in the NDH-1MS′-degradation mutants, indicating the existence of independent CO₂-uptake systems under high CO₂ conditions. The light-induced proton gradient across thylakoid membranes was significantly inhibited in ndhD-deletion mutants, suggesting that NdhDs functions in proton pumping. The carbonic anhydrase activity was suppressed partly in the cupA- or cupB-deletion mutant but severely in the mutant with both cupA and cupB deletion, indicating that CupA and CupB function in conversion of CO₂ to HCO₃⁻1. In turn, deletion of cup genes lowered the transthylakoid membrane proton gradient and deletion of ndhDs decreased the CO₂ hydration. Our results suggest that NDH-1M provides an alkaline region to activate Cup proteins involved in CO₂ uptake.
ISSN:0022-0957
1460-2431
DOI:10.1093/jxb/erx129