Genes encoding the alpha, gamma, delta, and four F0 subunits of ATP synthase constitute an operon in the cyanobacterium Anabaena sp. strain PCC 7120

Abstract

A cluster of genes encoding subunits of ATP synthase of Anabaena sp. strain PCC 7120 was cloned, and the nucleotide sequences of the genes were determined. This cluster, denoted atpi, consists of four Fo genes and three F1 genes encoding the subunits a (atpl), c (atpH), b' (atpG), b (atpF), 8 (atpD), a (aptA), and y (atpC) in that order. Closely linked upstream of the ATP synthase subunit genes is an open reading frame denoted gene 1, which is equivalent to the uncI gene of Escherichia coli. The atp1 gene cluster is at least 10 kilobase pairs distant in the genome from apt2, a cluster of genes encoding the (atpB) and E (atpE) subunits of the ATP synthase. This two-clustered ATP synthase gene arrangement is intermediate between those found in chloroplasts and E. coli. A unique feature of the Anabaena atpl cluster is overlap between the coding regions for atpF and atpD. The atpl cluster is transcribed as a single 7-kilobase polycistronic mRNA that initiates 140 base pairs upstream of gene 1. The deduced translation products for the Anabaena sp. strain PCC 7120 subunit genes are more similar to chloroplast ATP synthase subunits than to those of E. coli.The proton-translocating ATP synthase is a multimeric membrane protein complex that couples a transmembrane gradient of electrochemical potential energy produced during electron transport to formation of ATP. This ubiquitous enzyme is found in cell membranes of bacteria, in inner mitochondrial membranes, and in thylakoid membranes of plant chloroplasts (reviewed in references 15, 18, and 30). In all examples studied the enzyme consists of two multimeric components: an extrinsic portion, F1, composed of subunits denoted a, P, -y, 8, and , and in integral membrane portion Fo, composed of several subunits which vary depending on the source of the ATP synthase. In Escherichia coli and chloroplasts, the two systems used for comparison in this study, there are three (a to c) and four (I to IV) Fo subunits, respectively. In E. coli, genes encoding all eight subunits of the ATP synthase are tightly linked and cotranscribed (15). For the ATP synthase of chloroplasts, genes for some subunits are encoded in the nucleus and others are encoded in the organelle genome. The chloroplast ATP synthase genes of higher plants are organized into two separate transcriptional units: the and E genes are linked and cotranscribed (35), while a second cluster containing the I, III, IV, and a. subunit genes map many kilobase pairs away in a second ATP synthase gene cluster (9, 19). The -y, 8, and subunit II genes are nuclear (34).The cyanobacteria are procaryotes with an oxygenevolving photosynthetic system nearly identical to that of plant chloroplasts. The similarity between cyanobacterial and plant photosystems, as well as the procaryotelike features of chloroplasts, lends support to the proposal (28) that * Corresponding author. t Paper no.

Isolation of CF0CF1 from Chlamydomonas reinhardtii cw15 and the N‐terminal amino acid sequences of the CF0CF1 subunits

“…The apparent molecular mass of 7 kDa points to subunit III ('proteolipid'). Actually the obtained amino acid sequence is highly homologous to the sequences known for spinach [17] and Anabaena [18]. As the proteolipid from other sources [23] the N-terminal methionine of subunits Ill from Clamydomonas is formylated.…”

“…The assay medium contained 25 mM Tris buffer pH 8.3, 25 mM NaC1, 2. terminal sequence which resembles ~ from spinach chloroplasts [17] and Anabaena [18]. The atpD gene of Chlamydomonas resides in the nucleus and thus possesses a transit sequence (Berzborn et al, personal communication).…”

“…2. The obtained sequences were aligned to amino acid sequences derived from known DNA sequences of ATP synthase subunits of C. reinhardtii, spinach [17] and Anabaena [18], respectively.…”

Characterisation of a chloroplast‐encoded sec Y homologue and atpH from a chromophytic alga Evidence for a novel chloroplast genome organisation

“…3) and predicts a protein of 83 amino acids, which is highly conserved. P. luthevii AtpH is 87% identical to AtpH from the eyanobacteria [18,19], 88% identical to its counterpart in Odontella sinensus [20] and spinach [21], 90% identical to the wheat AtpH [22] and 91.3% identical to AtpH of Marchantia polymorpha [23].…”

The δ subunit of the chloroplast ATPase is plastid‐encoded in the diatom Odontella sinensis

“…In cyanobacteria they are arranged in two clusters, the atpB gene cluster containing the genes for subunits/3 (atpB) and e (atpE) and the atpA gene cluster including all Fo genes together with atpA and atpD, coding for subunits ~ and 8, respectively. The gene for subunit 3' (atpC) may be attached to the atpA gene cluster or isolated, dei~ending on the organism [8][9][10].…”