In:
Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 98, No. 20 ( 2001-09-25), p. 11789-11794
Abstract:
Cyanobacteria possess a CO 2 -concentating mechanism that
involves active CO 2 uptake and HCO \documentclass[12pt]{minimal} \usepackage{amsmath}
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\begin{document} \begin{equation*}{\mathrm{_{3}^{-}}}\end{equation*}\end{document} transport. For CO 2 uptake, we have identified two systems
in the cyanobacterium Synechocystis sp. strain PCC 6803,
one induced at low CO 2 and one constitutive. The low
CO 2 -induced system showed higher maximal activity and
higher affinity for CO 2 than the constitutive system. On
the basis of speculation that separate NAD(P)H dehydrogenase complexes were essential for each of these systems, we reasoned that inactivation
of one system would allow selection of mutants defective in the other. Thus, mutants unable to grow at pH 7.0 in air were recovered after
transformation of a Δ ndhD3 mutant with a
transposon-bearing library. Four of them had tags within slr1302 (designated cupB ), a homologue of sll1734 ( cupA ), which is cotranscribed
with ndhF3 and ndhD3 . The
Δ cupB, Δ ndhD4 , and
Δ ndhF4 mutants showed CO 2 -uptake
characteristics of the low CO 2 induced system observed
in wild type. In contrast, mutants Δ cupA, Δ ndhD3 , and Δ ndhF3 showed
characteristics of the constitutive CO 2 -uptake system.
Double mutants impaired in one component of each of the systems were unable to take up CO 2 and required high CO 2 for
growth. Phylogenetic analysis indicated that the ndhD3 / ndhD4 -, ndhF3 / ndhF4 -, and cupA / cupB -type genes are present only
in cyanobacteria. Most of the cyanobacterial strains studied possess the ndhD3 / ndhD4- , ndhF3 / ndhF4- , and cupA / cupB -type genes in pairs. Thus,
the two types of NAD(P)H dehydrogenase complexes essential for low CO 2 -induced and constitutive CO 2 -uptake systems
associated with the NdhD3/NdhF3/CupA-homologues and NdhD4/NdhF4/CupB-homologues, respectively, appear to be present in
these cyanobacterial strains but not in other organisms.
Type of Medium:
Online Resource
ISSN:
0027-8424
,
1091-6490
DOI:
10.1073/pnas.191258298
Language:
English
Publisher:
Proceedings of the National Academy of Sciences
Publication Date:
2001
detail.hit.zdb_id:
209104-5
detail.hit.zdb_id:
1461794-8
SSG:
11
SSG:
12
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