The Ligand-induced Structural Changes of Humanl-Arginine:Glycine Amidinotransferase

Fritsche, Erich; Humm, A.; Huber, Robert

doi:10.1074/jbc.274.5.3026

Cited by 23 publications

(25 citation statements)

References 39 publications

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“…There are two structurally well characterized amidinotransferases : the prokaryotic one from S. griseus, involved in the formation of streptomycin, and the eukaryotic type involved in the creatine biosynthetic pathway [7,8]. In these enzymes, structural di¡erences were correlated with variations in the amidino acceptor, inosamine phosphate or glycine in the prokaryotic and eukaryotic forms, respectively.…”

Section: Resultsmentioning

confidence: 99%

A novel gene encoding amidinotransferase in the cylindrospermopsin producing cyanobacterium Aphanizomenon ovalisporum

Shalev-Alon¹

2002

FEMS Microbiology Letters

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The hepatotoxin cylindrospermopsin is produced by several cyanobacteria species, which may flourish in tropical and sub‐tropical lakes. Biosynthesis of cylindrospermopsin is poorly understood but its chemical nature, and feeding experiments with stable isotopes, suggested that guanidinoacetic acid is the starter unit and indicated involvement of a polyketide synthase. We have identified a gene encoding an amidinotransferase from the cylindrospermopsin producing cyanobacterium Aphanizomenon ovalisporum. This is the first report on an amidinotransferase gene in cyanobacteria. It is likely to be involved in the formation of guanidinoacetic acid. The aoaA is located in a genomic region bearing genes encoding a polyketide synthase and a peptide synthetase, further supporting its putative role in cylindrospermopsin biosynthesis.

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Section: Resultsmentioning

confidence: 99%

A novel gene encoding amidinotransferase in the cylindrospermopsin producing cyanobacterium Aphanizomenon ovalisporum

Shalev-Alon¹

2002

FEMS Microbiology Letters

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“…Based on mutagenesis studies and structural data, catalytic mechanisms for DDAH and AGAT were proposed (25,26,30). The overall structural similarity of DDAH, AGAT, and ADI, the conservation of the catalytic triad, and the common orientation of the scissile bond relative to the catalytic cysteine suggest a similar reaction mechanism for the three enzymes.…”

Section: Proposed Michaelis Complex and Catalytic Mechanism-thementioning

confidence: 99%

Structural Insight into Arginine Degradation by Arginine Deiminase, an Antibacterial and Parasite Drug Target

Galkin

Kulakova

Sarıkaya

et al. 2004

Journal of Biological Chemistry

100

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L-Arginine deiminase (ADI) catalyzes the irreversible hydrolysis of arginine to citrulline and ammonia. ADI is involved in the first step of the most widespread anaerobic route of arginine degradation. ADI, missing in high eukaryotes, is a potential antimicrobial and antiparasitic drug target. We have determined the crystal structure of ADI from Pseudomonas aeruginosa by the multiwavelength anomalous diffraction method at 2.45 Å resolution. The structure exhibits similarity to other arginine-modifying or substituted arginine-modifying enzymes such as dimethylarginine dimethylaminohydrolase (DDAH), arginine:glycine amidinotransferase, and arginine:inosamine-phosphate amidinotransferase, despite the lack of significant amino acid sequence homology to these enzymes. The similarity spans a core domain comprising five ␤␤␣␤ motifs arranged in a circle around a 5-fold pseudosymmetry axis. ADI contains an additional ␣-helical domain of novel topology inserted between the first and the second ␤␤␣␤ modules. A catalytic triad, Cys-His-Glu/Asp (arranged in a different manner from that of the thiol proteases), seen in the other arginine-modifying enzymes is also conserved in ADI, as well as many other residues involved in substrate binding. Based on this conservation pattern and the assumption that the substrate binding mode is similar to that of DDAH, an ADI catalytic mechanism is proposed. The main players are Cys-406, which mounts the nucleophilic attack on the carbon atom of the guanidinium group of arginine, and His-278, which serves as a general base.

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“…This lid structure is formed by the loop composed of residues 298–302 (300‐flap) and helix 9 [10]. Asn300 and Met302 were also found to play a role in substrate binding and stability of the active site [8,10]. These two residues are conserved in all other known AGATs except CyrA.…”

Section: Introductionmentioning

confidence: 99%

Identification of two residues essential for the stringent substrate specificity and active site stability of the prokaryotic l‐arginine:glycine amidinotransferase CyrA

Muenchhoff¹,

Siddiqui²,

Neilan³

2012

The FEBS Journal

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A novel prokaryotic L-arginine:glycine amidinotransferase (CyrA; EC 2.1.4.1) is involved in the biosynthesis of the polyketide-derived cytotoxin cylindrospermopsin in the cyanobacterium Cylindrospermopsis raciborskii AWT250, and was previously characterized with regard to kinetic mechanism and substrate specificity [Muenchhoff J et al. (2010) FEBS J 277, 3844-3860]. In order to elucidate the structure-function-stability relationship of this enzyme, two residues in its active site were replaced with the residues that occur in the human L-arginine:glycine amidinotransferase (h-AGAT) at the corresponding positions (F245N and S247M), and a double variant carrying both substitutions was also created. In h-AGAT, both of these residues are critical for the function of this enzyme with regard to substrate binding, ligand-induced structural changes, and stability of the active site. In this study, we demonstrated that both single residue replacements resulted in a dramatic broadening of substrate specificity, but did not affect the kinetic mechanism. Experiments with substrate analogues indicate that donor substrates require a carboxylate group for binding. Evidence from initial velocity studies suggests that CyrA undergoes ligand-induced structural changes that involve Phe245. Stability parameters (T opt and T max ) of the CyrA variants differed from those of wild-type CyrA. Structural flexibilities of the wild type and all three variants were comparable on the basis of dynamic fluorescence quenching, indicating that changes in T opt are most likely attributable to localized effects within the active site. Overall, the results indicated that these two residues are essential for both stringent substrate specificity and the active site stability and flexibility of this unique cyanobacterial enzyme.

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The Ligand-induced Structural Changes of Humanl-Arginine:Glycine Amidinotransferase

Cited by 23 publications

References 39 publications

A novel gene encoding amidinotransferase in the cylindrospermopsin producing cyanobacterium Aphanizomenon ovalisporum

A novel gene encoding amidinotransferase in the cylindrospermopsin producing cyanobacterium Aphanizomenon ovalisporum

Structural Insight into Arginine Degradation by Arginine Deiminase, an Antibacterial and Parasite Drug Target

Identification of two residues essential for the stringent substrate specificity and active site stability of the prokaryotic l‐arginine:glycine amidinotransferase CyrA

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