The cyanobacterial tandem GAF domains from the cyaB2 adenylyl cyclase signal via both cAMP-binding sites

Bruder, Sandra; Linder, Jürgen; Martinez, Sergio E.; Zheng, Ning; Beavo, Joseph A.; Schultz, Joachim E.

doi:10.1073/pnas.0409917102

Cited by 36 publications

(50 citation statements)

References 17 publications

(44 reference statements)

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“…A comparison of E. coli fRMsr with one of the GAF domains of Anabaena adenylate cyclase (residues 79-230; PDB code 1YKD) reveals a clear structural basis for the observed ligand preferences (40,41). The Anabaena GAF domain binds cAMP, exhibits 22% sequence identity to E.coli fRMsr and superimposes with an rmsd of 1.44 Å for C ␣ carbon atoms (Fig.…”

Section: Discussionmentioning

confidence: 98%

See 1 more Smart Citation

Free methionine-( R )-sulfoxide reductase from Escherichia coli reveals a new GAF domain function

Zhi-dong

Johnson

Weissbach

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

129

138

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The reduction of methionine sulfoxide (MetO) is mediated by methionine sulfoxide reductases (Msr). The MsrA and MsrB families can reduce free MetO and MetO within a peptide or protein context. This process is stereospecific with the S-and R-forms of MetO repaired by MsrA and MsrB, respectively. Cell extracts from an MsrA ؊ B ؊ knockout of Escherichia coli have several remaining Msr activities. This study has identified an enzyme specific for the free form of Met-(R)-O, fRMsr, through proteomic analysis. The recombinant enzyme exhibits the same substrate specificity and is as active as MsrA family members. E. coli fRMsr is, however, 100-to 1,000-fold more active than non-selenocysteine-containing MsrB enzymes for free Met-(R)-O. The crystal structure of E. coli fRMsr was previously determined, but no known function was assigned. Thus, the function of this protein has now been determined. The structural similarity of the E. coli and yeast proteins suggests that most fRMsrs use three cysteine residues for catalysis and the formation of a disulfide bond to enclose a small active site cavity. This latter feature is most likely a key determinant of substrate specificity. Moreover, E. coli fRMsr is the first GAF domain family member to show enzymatic activity. Other GAF domain proteins substitute the Cys residues and others to specifically bind cyclic nucleotides, chromophores, and many other ligands for signal potentiation. Therefore, Met-(R)-O may represent a signaling molecule in response to oxidative stress and nutrients via the TOR pathway in some organisms. methionine oxidation ͉ methionine sulfoxide reductase

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Section: Discussionmentioning

confidence: 98%

“…Moreover, the tandem GAF domains of Anabaena adenylate cyclase and the mouse phosphodiesterase 2A, for example, dimerize (i.e., four GAF domains total) via different interfaces (40,41). As a result, these GAF dimers most likely interact with and modulate their downstream catalytic domains in unique ways.…”

Section: Discussionmentioning

confidence: 99%

Free methionine-( R )-sulfoxide reductase from Escherichia coli reveals a new GAF domain function

Zhi-dong

Johnson

Weissbach

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

129

138

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“…However, the highly similar cyaB1 AC has been enzymatically characterized and shown to be activated by cAMP binding to its GAF-B domains (11). A chimera containing the tandem GAF-A͞B domains from cyaB2 and the cyaB1 AC is activated almost exclusively by cAMP with an EC 50 of Ϸ1 M [see accompanying manuscript (12)]. Also, chimeras containing the tandem GAF-A͞B domains from rat PDE2A or PDE5 could be activated by cGMP and not cAMP as in the native PDE holoenzymes (ref.…”

Section: Discussionmentioning

confidence: 99%

“…This regulation is due to cAMP binding and signaling to the catalytic domain via the GAF-B domain (11). Another very similar adenylyl cyclase, cyaB2, likewise is stimulated by cAMP [see the accompanying article (12)]. Remarkably, a chimeric AC consisting of the PDE2 GAF domains and the cyaB1 catalytic domain can be activated by cGMP (11), suggesting that the tandem GAF domains in the mammalian PDEs and the cyanobacterial AC share common mechanisms for regulation of the enzymatic activities of their neighboring catalytic domains.…”

Section: G Af Domains (Named For Cyclic Gmp Adenylyl Cyclasementioning

confidence: 99%

Crystal structure of the tandem GAF domains from a cyanobacterial adenylyl cyclase: Modes of ligand binding and dimerization

Martinez

Bruder

Schultz

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

103

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In several species, GAF domains, which are widely expressed small-molecule-binding domains that regulate enzyme activity, are known to bind cyclic nucleotides. However, the molecular mechanism by which cyclic nucleotide binding affects enzyme activity is not known for any GAF domain. In the cyanobacterium, Anabaena, the cyaB1 and cyaB2 genes encode adenylyl cyclases that are stimulated by binding of cAMP to their N-terminal GAF domains. Replacement of the tandem GAF-A͞B domains in cyaB1 with the mammalian phosphodiesterase 2A GAF-A͞B tandem domains allows regulation of the chimeric protein by cGMP, suggesting a highly conserved mechanism of activation. Here, we describe the 1.9-Å crystal structure of the tandem GAF-A͞B domains of cyaB2 with bound cAMP and compare it to the previously reported structure of the PDE2A GAF-A͞B. Unexpectedly, the cyaB2 GAF-A͞B dimer is antiparallel, unlike the parallel dimer of PDE2A. Moreover, there is clear electron density for cAMP in both GAF-A and -B, whereas in PDE2A, cGMP is found only in GAF-B. Phosphate and ribose group contacts are similar to those in PDE2A. However, the purine-binding pockets appear very different from that in PDE2A GAF-B. Differences in the ␤2-␤3 loop suggest that this loop confers much of the ligand specificity in this and perhaps in many other GAF domains. Finally, a conserved asparagine appears to be a new addition to the signature NKFDE motif, and a mechanism for this motif to stabilize the cNMP-binding pocket is proposed.cAMP ͉ phosphodiesterase

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“…The studies have been hampered by the fact that cGMP concurrently serves as a substrate and as an allosteric regulator creating an unsolvable kinetic conundrum. Because the tandem GAF domains of mammalian PDEs are closely related to those of cyanobacterial ACs (6,13,14), we have replaced the cyanobacterial tandem GAF domain in the cyaB1 AC, which imparts cAMP regulation, with that of rPDE2a. The chimera is regulated by cGMP acting via the GAF B domain and uses ATP as a substrate (6).…”

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confidence: 99%

Characterization of the Tandem GAF Domain of Human Phosphodiesterase 5 Using a Cyanobacterial Adenylyl Cyclase as a Reporter Enzyme

Bruder

Schultz

2006

Journal of Biological Chemistry

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We analyzed cGMP signaling by the human phosphodiesterase 5 (hPDE5) tandem GAF domain based on a functional activation assay. The C-terminal catalytic domain of the cyanobacterial adenylyl cyclase (AC) cyaB1 was used as a reporter enzyme. We demonstrate functional coupling between the hPDE5 GAF ensemble and the AC resulting in a chimera stimulated 10-fold by cGMP. The hPDE5 GAF domain has an inhibitory effect on AC activity, which is released upon cGMP activation. Removal of 109 amino acids from the N terminus resulted in partial disengagement of the GAF domain and AC, i.e. in a 10-fold increase in basal activity, and affected cGMP affinity. The Ser-102 phosphorylation site of hPDE5 increased cGMP affinity, as shown by a 5-fold lower K D for cGMP in a S102D mutant, which mimicked complete modification. The function of the NKFDE motif, which is a signature of all GAF domains with known cyclic nucleotide binding capacity, was elucidated by targeted mutations. Data with either single and double mutants in either GAF A or GAF B or a quadruple mutant affecting both subdomains simultaneously indicated that it is impossible to functionally assign cGMP binding and intramolecular signaling to either GAF A or B of hPDE5. Both subdomains are structurally and functionally interdependent and act in concert in regulating cycaB1 AC and, most likely, also hPDE5.In essentially all eukaryotic cells, cAMP and cGMP act as second messengers. Therefore the concentration of these nucleotides is meticulously regulated by the rates of biosynthesis and breakdown (1, 2). Although for years most studies have focused on mammalian ACs, 2 more recently PDEs have come into focus. Based on biochemical properties and sequence alignments, mammalian PDEs have been grouped into 11 families (PDE1-PDE11). All catalytic domains are similar (20 -45% identity (3)), and peculiar regulatory features are mediated by differing N-terminal domains. PDEs 2, 5, 6, 10, and 11 contain N-terminal tandem GAF domains (the acronym derives from proteins of initial identification: mammalian cGMP-binding PDEs, Anabaena adenylyl cyclases, and Escherichia coli transcription factor FhlA (4, 5)). To date, GAF domains have been identified in more than 3000 proteins. They bind a variety of small ligands and promote protein dimerization (2, 6 -8).The tandem GAF domains in mammalian PDEs 2, 5, and 6, which bind cGMP, have been analyzed intensively (2, 7-12). The studies have been hampered by the fact that cGMP concurrently serves as a substrate and as an allosteric regulator creating an unsolvable kinetic conundrum. Because the tandem GAF domains of mammalian PDEs are closely related to those of cyanobacterial ACs (6, 13, 14), we have replaced the cyanobacterial tandem GAF domain in the cyaB1 AC, which imparts cAMP regulation, with that of rPDE2a. The chimera is regulated by cGMP acting via the GAF B domain and uses ATP as a substrate (6).Here, we successfully replaced the tandem GAF domain of the cyaB1 AC with that of the hPDE5, again and surprisingly generating a cGMP-regulat...

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The cyanobacterial tandem GAF domains from the cyaB2 adenylyl cyclase signal via both cAMP-binding sites

Cited by 36 publications

References 17 publications

Free methionine-( R )-sulfoxide reductase from Escherichia coli reveals a new GAF domain function

Free methionine-( R )-sulfoxide reductase from Escherichia coli reveals a new GAF domain function

Crystal structure of the tandem GAF domains from a cyanobacterial adenylyl cyclase: Modes of ligand binding and dimerization

Characterization of the Tandem GAF Domain of Human Phosphodiesterase 5 Using a Cyanobacterial Adenylyl Cyclase as a Reporter Enzyme

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