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Bustad HJ, Kallio JP, Laitaoja M, Toska K, Kursula I, Martinez A, Jänis J. Characterization of porphobilinogen deaminase mutants reveals that arginine-173 is crucial for polypyrrole elongation mechanism. iScience 2021; 24:102152. [PMID: 33665570 PMCID: PMC7907807 DOI: 10.1016/j.isci.2021.102152] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 12/03/2020] [Accepted: 02/02/2021] [Indexed: 11/16/2022] Open
Abstract
Porphobilinogen deaminase (PBGD), the third enzyme in the heme biosynthesis, catalyzes the sequential coupling of four porphobilinogen (PBG) molecules into a heme precursor. Mutations in PBGD are associated with acute intermittent porphyria (AIP), a rare metabolic disorder. We used Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) to demonstrate that wild-type PBGD and AIP-associated mutant R167W both existed as holoenzymes (Eholo) covalently attached to the dipyrromethane cofactor, and three intermediate complexes, ES, ES2, and ES3, where S represents PBG. In contrast, only ES2 was detected in AIP-associated mutant R173W, indicating that the formation of ES3 is inhibited. The R173W crystal structure in the ES2-state revealed major rearrangements of the loops around the active site, compared to wild-type PBGD in the Eholo-state. These results contribute to elucidating the structural pathogenesis of two common AIP-associated mutations and reveal the important structural role of Arg173 in the polypyrrole elongation mechanism.
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Affiliation(s)
- Helene J Bustad
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway
| | - Juha P Kallio
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway
| | - Mikko Laitaoja
- Department of Chemistry, University of Eastern Finland, 80130 Joensuu, Finland
| | - Karen Toska
- Norwegian Porphyria Centre (NAPOS), Department for Medical Biochemistry and Pharmacology, Haukeland University Hospital, 5021 Bergen, Norway
| | - Inari Kursula
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway.,Faculty of Biochemistry and Molecular Medicine, University of Oulu, 90570 Oulu, Finland
| | - Aurora Martinez
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway
| | - Janne Jänis
- Department of Chemistry, University of Eastern Finland, 80130 Joensuu, Finland
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Guo J, Erskine P, Coker AR, Wood SP, Cooper JB. Structural studies of domain movement in active-site mutants of porphobilinogen deaminase from Bacillus megaterium. Acta Crystallogr F Struct Biol Commun 2017; 73:612-620. [PMID: 29095155 PMCID: PMC5683031 DOI: 10.1107/s2053230x17015436] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 10/23/2017] [Indexed: 11/10/2022] Open
Abstract
The enzyme porphobilinogen deaminase (PBGD) is one of the key enzymes in tetrapyrrole biosynthesis. It catalyses the formation of a linear tetrapyrrole from four molecules of the substrate porphobilinogen (PBG). It has a dipyrromethane cofactor (DPM) in the active site which is covalently linked to a conserved cysteine residue through a thioether bridge. The substrate molecules are linked to the cofactor in a stepwise head-to-tail manner during the reaction, which is catalysed by a conserved aspartate residue: Asp82 in the B. megaterium enzyme. Three mutations have been made affecting Asp82 (D82A, D82E and D82N) and their crystal structures have been determined at resolutions of 2.7, 1.8 and 1.9 Å, respectively. These structures reveal that whilst the D82E mutant possesses the DPM cofactor, in the D82N and D82A mutants the cofactor is likely to be missing, incompletely assembled or disordered. Comparison of the mutant PBGD structures with that of the wild-type enzyme shows that there are significant domain movements and suggests that the enzyme adopts `open' and `closed' conformations, potentially in response to substrate binding.
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Affiliation(s)
- Jingxu Guo
- Division of Medicine, University College London, Gower Street, London WC1E 6BT, England
| | - Peter Erskine
- Division of Medicine, University College London, Gower Street, London WC1E 6BT, England
- Department of Biological Sciences, Birkbeck, University of London, Malet Street, Bloomsbury, London WC1E 7HX, England
| | - Alun R. Coker
- Division of Medicine, University College London, Gower Street, London WC1E 6BT, England
| | - Steve P. Wood
- Division of Medicine, University College London, Gower Street, London WC1E 6BT, England
| | - Jonathan B. Cooper
- Division of Medicine, University College London, Gower Street, London WC1E 6BT, England
- Department of Biological Sciences, Birkbeck, University of London, Malet Street, Bloomsbury, London WC1E 7HX, England
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Azim N, Deery E, Warren MJ, Wolfenden BAA, Erskine P, Cooper JB, Coker A, Wood SP, Akhtar M. Structural evidence for the partially oxidized dipyrromethene and dipyrromethanone forms of the cofactor of porphobilinogen deaminase: structures of the Bacillus megaterium enzyme at near-atomic resolution. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2014; 70:744-51. [PMID: 24598743 PMCID: PMC3949521 DOI: 10.1107/s139900471303294x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 12/04/2013] [Indexed: 11/10/2022]
Abstract
The enzyme porphobilinogen deaminase (PBGD; hydroxymethylbilane synthase; EC 2.5.1.61) catalyses an early step of the tetrapyrrole-biosynthesis pathway in which four molecules of the monopyrrole porphobilinogen are condensed to form a linear tetrapyrrole. The enzyme possesses a dipyrromethane cofactor, which is covalently linked by a thioether bridge to an invariant cysteine residue (Cys241 in the Bacillus megaterium enzyme). The cofactor is extended during the reaction by the sequential addition of the four substrate molecules, which are released as a linear tetrapyrrole product. Expression in Escherichia coli of a His-tagged form of B. megaterium PBGD has permitted the X-ray analysis of the enzyme from this species at high resolution, showing that the cofactor becomes progressively oxidized to the dipyrromethene and dipyrromethanone forms. In previously solved PBGD structures, the oxidized cofactor is in the dipyromethenone form, in which both pyrrole rings are approximately coplanar. In contrast, the oxidized cofactor in the B. megaterium enzyme appears to be in the dipyrromethanone form, in which the C atom at the bridging α-position of the outer pyrrole ring is very clearly in a tetrahedral configuration. It is suggested that the pink colour of the freshly purified protein is owing to the presence of the dipyrromethene form of the cofactor which, in the structure reported here, adopts the same conformation as the fully reduced dipyrromethane form.
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Affiliation(s)
- N. Azim
- School of Biological Sciences, University of Punjab, New Campus, Lahore-54590, Pakistan
| | - E. Deery
- School of Biosciences, University of Kent, Stacey Building, Canterbury CT2 7NJ, England
| | - M. J. Warren
- School of Biosciences, University of Kent, Stacey Building, Canterbury CT2 7NJ, England
| | - B. A. A. Wolfenden
- Laboratory of Protein Crystallography, Centre for Amyloidosis and Acute Phase Proteins, UCL Division of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF, England
| | - P. Erskine
- Laboratory of Protein Crystallography, Centre for Amyloidosis and Acute Phase Proteins, UCL Division of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF, England
| | - J. B. Cooper
- Laboratory of Protein Crystallography, Centre for Amyloidosis and Acute Phase Proteins, UCL Division of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF, England
| | - A. Coker
- Laboratory of Protein Crystallography, Centre for Amyloidosis and Acute Phase Proteins, UCL Division of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF, England
| | - S. P. Wood
- Laboratory of Protein Crystallography, Centre for Amyloidosis and Acute Phase Proteins, UCL Division of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF, England
| | - M. Akhtar
- School of Biological Sciences, University of Punjab, New Campus, Lahore-54590, Pakistan
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Conformational stability and activity analysis of two hydroxymethylbilane synthase mutants, K132N and V215E, with different phenotypic association with acute intermittent porphyria. Biosci Rep 2013; 33:BSR20130045. [PMID: 23815679 PMCID: PMC3738108 DOI: 10.1042/bsr20130045] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The autosomal dominantly inherited disease AIP (acute intermittent porphyria) is caused by mutations in HMBS [hydroxymethylbilane synthase; also known as PBG (porphobilinogen) deaminase], the third enzyme in the haem biosynthesis pathway. Enzyme-intermediates with increasing number of PBG molecules are formed during the catalysis of HMBS. In this work, we studied the two uncharacterized mutants K132N and V215E comparative with wt (wild-type) HMBS and to the previously reported AIP-associated mutants R116W, R167W and R173W. These mainly present defects in conformational stability (R116W), enzyme kinetics (R167W) or both (R173W). A combination of native PAGE, CD, DSF (differential scanning fluorimetry) and ion-exchange chromatography was used to study conformational stability and activity of the recombinant enzymes. We also investigated the distribution of intermediates corresponding to specific elongation stages. It is well known that the thermostability of HMBS increases when the DPM (dipyrromethane) cofactor binds to the apoenzyme and the holoenzyme is formed. Interestingly, a decrease in thermal stability was measured concomitant to elongation of the pyrrole chain, indicating a loosening of the structure prior to product release. No conformational or kinetic defect was observed for the K132N mutant, whereas V215E presented lower conformational stability and probably a perturbed elongation process. This is in accordance with the high association of V215E with AIP. Our results contribute to interpret the molecular mechanisms for dysfunction of HMBS mutants and to establish genotype–phenotype relations for AIP.
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Roberts A, Gill R, Hussey RJ, Mikolajek H, Erskine PT, Cooper JB, Wood SP, Chrystal EJT, Shoolingin-Jordan PM. Insights into the mechanism of pyrrole polymerization catalysed by porphobilinogen deaminase: high-resolution X-ray studies of the Arabidopsis thaliana enzyme. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2013; 69:471-85. [PMID: 23519422 DOI: 10.1107/s0907444912052134] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 12/31/2012] [Indexed: 11/10/2022]
Abstract
The enzyme porphobilinogen deaminase (PBGD; hydroxymethylbilane synthase; EC 2.5.1.61) catalyses a key early step of the haem- and chlorophyll-biosynthesis pathways in which four molecules of the monopyrrole porphobilinogen are condensed to form a linear tetrapyrrole. The active site possesses an unusual dipyrromethane cofactor which is extended during the reaction by the sequential addition of the four substrate molecules. The cofactor is linked covalently to the enzyme through a thioether bridge to the invariant Cys254. Until recently, structural data have only been available for the Escherichia coli and human forms of the enzyme. The expression of a codon-optimized gene for PBGD from Arabidopsis thaliana (thale cress) has permitted for the first time the X-ray analysis of the enzyme from a higher plant species at 1.45 Å resolution. The A. thaliana structure differs appreciably from the E. coli and human forms of the enzyme in that the active site is shielded by an extensive well defined loop region (residues 60-70) formed by highly conserved residues. This loop is completely disordered and uncharacterized in the E. coli and human PBGD structures. The new structure establishes that the dipyrromethane cofactor of the enzyme has become oxidized to the dipyrromethenone form, with both pyrrole groups approximately coplanar. Modelling of an intermediate of the elongation process into the active site suggests that the interactions observed between the two pyrrole rings of the cofactor and the active-site residues are highly specific and are most likely to represent the catalytically relevant binding mode. During the elongation cycle, it is thought that domain movements cause the bound cofactor and polypyrrole intermediates to move past the catalytic machinery in a stepwise manner, thus permitting the binding of additional substrate moieties and completion of the tetrapyrrole product. Such a model would allow the condensation reactions to be driven by the extensive interactions that are observed between the enzyme and the dipyrromethane cofactor, coupled with acid-base catalysis provided by the invariant aspartate residue Asp95.
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Affiliation(s)
- A Roberts
- School of Biological Sciences, University of Southampton, Southampton SO16 1BJ, England
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6
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Effect of IPTG amount on apo- and holo- forms of glycerophosphate oxidase expressed in Escherichia coli. Protein Expr Purif 2010; 75:133-7. [PMID: 20736068 DOI: 10.1016/j.pep.2010.08.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Revised: 08/18/2010] [Accepted: 08/18/2010] [Indexed: 11/23/2022]
Abstract
Escherichia coli has proved to be a successful host for the expression of many heterologous proteins, and much efforts have been made toward improving recombinant protein expression including the usage of strong promoters and co-expression with chaperones. But little attention was paid on the relation between expression level and function of the target protein. Glycerophosphate oxidase (GPO) is a protein with FAD cofactor (without free cysteine and disulfide bonds).It was observed that the specific activity of GPO dramatically decreased with the increase of inducer IPTG. In addition, the stability of it decreased correspondingly. The structural difference of samples expressed under varying IPTG was investigated using size-exclusion and reverse-phase high performance liquid chromatography, together with CD spectrum. It was found that the conformation of peptide and organization of subunits were not affected. The loss of specific activity and stability were correlated to incomplete attachment of FAD onto GPO. These results revealed that synthesis speed should be controlled either by reduction of IPTG amount or using weak promoters in the production of GPO.
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7
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Jordan PM. The biosynthesis of uroporphyrinogen III: mechanism of action of porphobilinogen deaminase. CIBA FOUNDATION SYMPOSIUM 2007; 180:70-89; discussion 89-96. [PMID: 7842863 DOI: 10.1002/9780470514535.ch5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The biosynthesis of the uroporphyrinogen III macrocycle from porphobilinogen requires the sequential participation of two enzymes--porphobilinogen deaminase (1-hydroxymethylbilane synthase, EC 4.3.1.8) and uroporphyrinogen III synthase (cosynthase, EC 4.2.1.75). The product of the deaminase-catalysed reaction is a highly unstable 1-hydroxymethylbilane called preuroporphyrinogen which acts as the substrate for the uroporphyrinogen III synthase, resulting in the exclusive formation of uroporphyrinogen III. In the absence of the synthase, preuroporphyrinogen cyclizes spontaneously to give uroporphyrinogen I. Porphobilinogen deaminase contains a dipyrromethane cofactor that acts as a primer onto which the tetrapyrrole chain is built. The assembly process occurs in stages through enzyme-intermediate complexes, ES, ES2, ES3 and ES4. The negatively charged carboxylates of the cofactor, substrate and intermediate complexes interact with positively charged amino acid side chains in the catalytic cleft. Mutagenesis of conserved arginines has dramatic effects on the assembly of the dipyrromethane cofactor and on the tetrapolymerization process. During the polymerization, the enzyme changes conformation to accommodate the elongating pyrrole chain. The structure of the deaminase from Escherichia coli has been determined by X-ray crystallography at 1.9A resolution and gives important insight into the enzymic mechanism. Aspartate 84 plays a key role in catalysis and its substitution by glutamate reduces kcat by two orders of magnitude.
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Affiliation(s)
- P M Jordan
- School of Biological Sciences, Queen Mary and Westfield College, University of London, UK
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8
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Pichon-Santander C, Ian Scott A. Studies on the formation of porphyrinogens from monopyrroles in presence of the enzymes PBG deaminase and/or Uro’gen III synthase. Tetrahedron Lett 2005. [DOI: 10.1016/j.tetlet.2005.10.063] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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9
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Abstract
The chronology of the discoveries along the pathway of vitamin B12 biosynthesis is reviewed from a personal perspective, including discussion of the most recent finding that two pathways to B12 exist--one aerobic and one anaerobic--which differ mainly in the ring contraction mechanisms which convert porphyrin to corrin.
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Affiliation(s)
- A I Scott
- Center for Biological NMR, Chemistry Department, Texas A&M University, College Station 77843-3255, USA.
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10
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Fujino E, Fujino T, Karita S, Kimura T, Sakka K, Ohmiya K. Purification and characterization of the clostridium josui porphobilinogen deaminase encoded by the hemC gene from a recombinant escherichia coli. J Biosci Bioeng 1999; 87:535-7. [PMID: 16232511 DOI: 10.1016/s1389-1723(99)80106-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/1998] [Accepted: 12/24/1998] [Indexed: 11/19/2022]
Abstract
The porphobilinogen deaminase encoded by the Clostridium josui hemC gene was purified from a recombinant Escherichia coli strain and its properties were characterized. The optimal temperature and pH of the purified enzyme were 65 degrees C and 7.0, respectively. This enzyme was quite thermostable: it retained 86% of the original activity after incubation at 70 degrees C for 1 h. The Km and Vmax values of the enzyme were 65 microM and 3.3 micromol/h/mg for porphobilinogen, respectively.
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Affiliation(s)
- E Fujino
- Faculty of Bioresources, Mie University, Tsu, Mie 514-8507, Japan
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11
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Awan SJ, Siligardi G, Shoolingin-Jordan PM, Warren MJ. Reconstitution of the holoenzyme form of Escherichia coli porphobilinogen deaminase from apoenzyme with porphobilinogen and preuroporphyrinogen: a study using circular dichroism spectroscopy. Biochemistry 1997; 36:9273-82. [PMID: 9230062 DOI: 10.1021/bi9702602] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Porphobilinogen deaminase (PBG-D), an early enzyme of the tetrapyrrole biosynthetic pathway, catalyzes the formation of a tetrapyrrole chain, preuroporphyrinogen, from four molecules of porphobilinogen (PBG). The PBG-D apoenzyme is responsible for the autocatalytic synthesis and covalent attachment of a dipyrromethane cofactor at its active site. In this paper an efficient method for the purification of Escherichia coli PBG-D apoenzyme using an affinity chromatography resin is reported. Circular dichroism (CD) spectra of apoenzyme and holoenzyme were recorded and significant differences in both the backbone and aromatic region of the spectra were observed. The differences in the spectra allowed the reconstitution of holoenzyme from purified apoenzyme with PBG and preuroporphyrinogen in solution to be monitored separately by CD. Apoenzyme incubated with preuroporhyrinogen gave a CD spectrum that was much more like the CD spectrum of holoenzyme than apoenzyme incubated with PBG. The results showed clearly that the cofactor was generated much more rapidly from preuroporphyrinogen than from PBG. Changes in the CD spectrum associated with the aromatic side-chain region, in particular the contribution assigned to phenylalanine-62, were found to correlate well with the activity of the reconstituted enzyme. Phenylalanine-62 is located in close proximity to the cofactor and acts as a sensitive probe to active-site changes. The stability of the holoenzyme and apoenzyme were compared with respect to both heat and susceptibility to proteolysis. The results were consistent with a model for the apoenzyme in which, in the absence of the cofactor, the three domains of the protein are held less rigidly together, thereby making the protein more susceptible to heat denaturation and proteolysis. The CD spectrum of the holoenzyme was found to be similar at both pH 5.1 and 7.4, suggesting that the crystal structure, determined at pH 5.1, is likely to be similar at physiological pH values.
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Affiliation(s)
- S J Awan
- Department of Molecular Genetics, Institute of Ophthalmology, University College London, Bath Street, London EC1V 9EL, England
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12
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Shoolingin-Jordan PM, Warren MJ, Awan SJ. Dipyrromethane cofactor assembly of porphobilinogen deaminase: formation of apoenzyme and preparation of holoenzyme. Methods Enzymol 1997; 281:317-27. [PMID: 9250996 DOI: 10.1016/s0076-6879(97)81038-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- P M Shoolingin-Jordan
- Department of Biochemistry, School of Biological Science, University of Southampton, United Kingdom
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13
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Roessner CA, Scott AI. Genetically engineered synthesis of natural products: from alkaloids to corrins. Annu Rev Microbiol 1996; 50:467-90. [PMID: 8905088 DOI: 10.1146/annurev.micro.50.1.467] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Because many natural products are of biological and medicinal importance, methods are continually being sought for studying their biosynthetic pathways, which may eventually result in increased production and the generation of novel compounds. Advances in genetic engineering have enabled the homologous or heterologous expression of many natural product biosynthetic genes from divergent sources, resulting in a supply of enzymes not readily available by isolation from the producing organism. Mixing and matching of these enzymes in cell-free reactions can provide information, not available by any other means, about enzyme mechanisms, pathway intermediates, and possible variations in the structure of the final product.
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Affiliation(s)
- C A Roessner
- Department of Chemistry, Texas A&M University, College Station 77843-3255, USA
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14
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Shoolingin-Jordan PM, Warren MJ, Awan SJ. Discovery that the assembly of the dipyrromethane cofactor of porphobilinogen deaminase holoenzyme proceeds initially by the reaction of preuroporphyrinogen with the apoenzyme. Biochem J 1996; 316 ( Pt 2):373-6. [PMID: 8687374 PMCID: PMC1217358 DOI: 10.1042/bj3160373] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The assembly process of the dipyrromethane cofactor of Escherichia coli porphobilinogen deaminase holoenzyme is initiated by the reaction of the porphobilinogen deaminase apoenzyme with preuroporphyrinogen. The resulting enzyme-bound tetrapyrrole (bilane) is equivalent to the holoenzyme intermediate complex ES2 and yields the dipyrromethane cofactor by reactions of the normal catalytic cycle. These observations indicate that preuroporphyrinogen, rather than porphobilinogen, is the preferred precursor for the dipyrromethane cofactor and explain the existence of the D84A and D84N deaminase mutants as catalytically inactive ES2 complexes.
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Affiliation(s)
- P M Shoolingin-Jordan
- Biochemistry Department, School of Biological Sciences, University of Southampton, U.K
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15
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Roessner CA, Scott AI. Achieving natural product synthesis and diversity via catalytic networking ex vivo. CHEMISTRY & BIOLOGY 1996; 3:325-30. [PMID: 8807860 DOI: 10.1016/s1074-5521(96)90114-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Recent studies on ex vivo synthesis of natural products reveal that even complex multistep pathways can be successfully reconstructed. Genetic engineering of such reconstituted pathways has already been used to generate 'unnatural' natural products related to the original compound. In the future, it may be possible to use these approaches to make natural products that are currently inaccessible to conventional synthesis.
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Affiliation(s)
- C A Roessner
- Center for Biological NMR, Department of Chemistry, Texas A&M University, College Station, TX 77843-3255, USA
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16
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Louie GV, Brownlie PD, Lambert R, Cooper JB, Blundell TL, Wood SP, Malashkevich VN, Hädener A, Warren MJ, Shoolingin-Jordan PM. The three-dimensional structure of Escherichia coli porphobilinogen deaminase at 1.76-A resolution. Proteins 1996; 25:48-78. [PMID: 8727319 DOI: 10.1002/(sici)1097-0134(199605)25:1<48::aid-prot5>3.0.co;2-g] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Porphobilinogen deaminase (PBGD) catalyses the polymerization of four molecules of porphobilinogen to form the 1-hydroxymethylbilane, preuroporphyrinogen, a key intermediate in the biosynthesis of tetrapyrroles. The three-dimensional structure of wild-type PBGD from Escherichia coli has been determined by multiple isomorphous replacement and refined to a crystallographic R-factor of 0.188 at 1.76 A resolution. the polypeptide chain of PBGD is folded into three alpha/beta domains. Domains 1 and 2 have a similar overall topology, based on a five-stranded, mixed beta-sheet. These two domains, which are linked by two hinge segments but otherwise make few direct interactions, form an extensive active site cleft at their interface. Domain 3, an open-faced, anti-parallel sheet of three strands, interacts approximately equally with the other two domains. The dipyrromethane cofactor is covalently attached to a cysteine side-chain borne on a flexible loop of domain 3. The cofactor serves as a primer for the assembly of the tetrapyrrole product and is held within the active site cleft by hydrogen-bonds and salt-bridges that are formed between its acetate and propionate side-groups and the polypeptide chain. The structure of a variant of PBGD, in which the methionines have been replaced with selenomethionines, has also been determined. The cofactor, in the native and functional form of the enzyme, adopts a conformation in which the second pyrrole ring (C2) occupies an internal position in the active site cleft. On oxidation, however, this C2 ring of the cofactor adopts a more external position that may correspond approximately to the site of substrate binding and polypyrrole chain elongation. The side-chain of Asp84 hydrogen-bonds the hydrogen atoms of both cofactor pyrrole nitrogens and also potentially the hydrogen atom of the pyrrole nitrogen of the porphobilinogen molecule bound to the proposed substrate binding site. This group has a key catalytic role, possibly in stabilizing the positive charges that develop on the pyrrole nitrogens during the ring-coupling reactions. Possible mechanisms for the processive elongation of the polypyrrole chain involve: accommodation of the elongating chain within the active site cleft, coupled with shifts in the relative positions of domains 1 and 2 to carry the terminal ring into the appropriate position at the catalytic site; or sequential translocation of the elongating polypyrrole chain, attached to the cofactor on domain 3, through the active site cleft by the progressive movement of domain 3 with respect to domains 1 and 2. Other mechanisms are considered although the amino acid sequence comparisons between PBGDs from all species suggest they share the same three-dimensional structure and mechanism of activity.
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Affiliation(s)
- G V Louie
- Department of Crystallography, Birkbeck College, University of London, United Kingdom
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Warren MJ, Gul S, Aplin RT, Scott AI, Roessner CA, O'Grady P, Shoolingin-Jordan PM. Evidence for conformational changes in Escherichia coli porphobilinogen deaminase during stepwise pyrrole chain elongation monitored by increased reactivity of cysteine-134 to alkylation by N-ethylmaleimide. Biochemistry 1995; 34:11288-95. [PMID: 7669787 DOI: 10.1021/bi00035a038] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Porphobilinogen deaminase from Escherichia coli becomes progressively more susceptible to inactivation by the thiophilic reagent N-ethylmaleimide (NEM) as the catalytic cycle proceeds through the enzyme-intermediate complexes ES, ES2, ES3, and ES4. Site-directed mutagenesis of potentially reactive cysteines has been used to identify cysteine-134 as the key residue that becomes modified by the reagent and leads to inactivation. Since cysteine-134 is buried at the interface between domains 2 and 3 of the E. coli deaminase molecule, the observations suggest that a stepwise conformational change occurs between these domains during each stage of tetrapyrrole assembly. Interestingly, mutation of the invariant active-site cysteine-242 to serine leads to an enzyme with up to a third of the catalytic activity found in the wild-type enzyme. Electrospray mass spectrometry indicates that serine can substitute for cysteine as the dipyrromethane cofactor attachment site.
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Affiliation(s)
- M J Warren
- Department of Medical Genetics, University of London, U.K
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Abstract
Acute intermittent porphyria is an inherited disease of haem biosynthesis that results from mutation of the gene for the enzyme porphobilinogen deaminase. Many different mutations have been located throughout the gene. The three-dimensional structure of the enzyme helps in understanding how these mutations lead to inactivation even when, in some cases, the mutated product is abundant and folded correctly.
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Affiliation(s)
- S Wood
- Laboratory of Molecular Biology, Department of Crystallography, Birkbeck College, University of London, UK.
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Shoolingin-Jordan PM. Porphobilinogen deaminase and uroporphyrinogen III synthase: structure, molecular biology, and mechanism. J Bioenerg Biomembr 1995; 27:181-95. [PMID: 7592565 DOI: 10.1007/bf02110033] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Porphobilinogen deaminase (hydroxymethylbilane synthase) and uroporphyrinogen III synthase (uroporphyrinogen III cosynthase) catalyze the transformation of four molecules of porphobilinogen, via the 1-hydroxymethylbilane, preuroporphyrinogen, into uroporphyrinogen III. A combination of studies involving protein chemistry, molecular biology, site-directed mutagenesis, and the use of chemically synthesized substrate analogs and inhibitors is helping to unravel the complex mechanisms by which the two enzymes function. The determination of the X-ray structure of E. coli porphobilinogen deaminase at 1.76 A resolution has provided the springboard for the design of further experiments to elucidate the precise mechanism for the assembly of both the dipyrromethane cofactor and the tetrapyrrole chain. The human deaminase structure has been modeled from the E. coli structure and has led to a molecular explanation for the disease acute intermittent porphyria. Molecular modeling has also been employed to stimulate the spiro-mechanism of uroporphyrinogen III synthase.
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Affiliation(s)
- P M Shoolingin-Jordan
- Department of Biochemistry, School of Biological Sciences, University of Southampton, Hants, England
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20
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Brownlie PD, Lambert R, Louie GV, Jordan PM, Blundell TL, Warren MJ, Cooper JB, Wood SP. The three-dimensional structures of mutants of porphobilinogen deaminase: toward an understanding of the structural basis of acute intermittent porphyria. Protein Sci 1994; 3:1644-50. [PMID: 7849582 PMCID: PMC2142616 DOI: 10.1002/pro.5560031004] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Mutations in the human gene for the enzyme porphobilinogen deaminase give rise to an inherited disease of heme biosynthesis, acute intermittent porphyria. Knowledge of the 3-dimensional structure of human porphobilinogen deaminase, based on the structure of the bacterial enzyme, allows correlation of structure with gene organization and leads to an understanding of the relationship between mutations in the gene, structural and functional changes of the enzyme, and the symptoms of the disease. Most mutations occur in exons 10 and 12, often changing amino acids in the active site. Several of these are shown to be involved in binding the primer or substrate; none modifies Asp 84, which is essential for catalytic activity.
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Affiliation(s)
- P D Brownlie
- Department of Crystallography, Birkbeck College, University of London, United Kingdom
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21
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Jones RM, Jordan PM. Purification and properties of porphobilinogen deaminase from Arabidopsis thaliana. Biochem J 1994; 299 ( Pt 3):895-902. [PMID: 8192681 PMCID: PMC1138105 DOI: 10.1042/bj2990895] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Porphobilinogen deaminase (EC 4.3.1.8) has been purified to homogeneity (16,000-fold) from the plant Arabidopsis thaliana in yields of 8%. The deaminase is a monomer of M(r) 35,000, as shown by SDS/PAGE, and 31,000, using gel-filtration chromatography. The pure enzyme has a Vmax. of 4.5 mumol/h per mg and a Km of 17 +/- 4 microM. Determination of the pI and pH optimum revealed values of 5.2 and 8.0 respectively. The sequence of the N-terminus was found to be NH2-XVAVEQKTRTAI. The deaminase is heat-stable up to 70 degrees C and is inhibited by NH3 and hydroxylamine. The enzyme is inactivated by arginine-, histidine- and lysine-specific reagents. Incubation with the substrate analogue and suicide inhibitor, 2-bromoporphobilinogen, results in chain termination and in inactivation.
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Affiliation(s)
- R M Jones
- School of Biological Sciences, Queen Mary and Westfield College, University of London, U.K
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23
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Scott AI. Wie die Natur Vitamin B12 synthetisiert – ein Überblick über die letzten vier Milliarden Jahre. Angew Chem Int Ed Engl 1993. [DOI: 10.1002/ange.19931050904] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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24
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Scott AI. How Nature Synthesizes Vitamin B12?A Survey of the Last Four Billion Years. ACTA ACUST UNITED AC 1993. [DOI: 10.1002/anie.199312233] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Louie GV, Brownlie PD, Lambert R, Cooper JB, Blundell TL, Wood SP, Warren MJ, Woodcock SC, Jordan PM. Structure of porphobilinogen deaminase reveals a flexible multidomain polymerase with a single catalytic site. Nature 1992; 359:33-9. [PMID: 1522882 DOI: 10.1038/359033a0] [Citation(s) in RCA: 133] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The three-domain structure of porphobilinogen deaminase, a key enzyme in the biosynthetic pathway of tetrapyrroles, has been defined by X-ray analysis at 1.9 A resolution. Two of the domains structurally resemble the transferrins and periplasmic binding proteins. The dipyrromethane cofactor is covalently linked to domain 3 but is bound by extensive salt-bridges and hydrogen-bonds within the cleft between domains 1 and 2, at a position corresponding to the binding sites for small-molecule ligands in the analogous proteins. The X-ray structure and results from site-directed mutagenesis provide evidence for a single catalytic site. Interdomain flexibility may aid elongation of the polypyrrole product in the active-site cleft of the enzyme.
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Affiliation(s)
- G V Louie
- Department of Crystallography, Birkbeck College, University of London, UK
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26
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Keng T, Richard C, Larocque R. Structure and regulation of yeast HEM3, the gene for porphobilinogen deaminase. MOLECULAR & GENERAL GENETICS : MGG 1992; 234:233-43. [PMID: 1508149 DOI: 10.1007/bf00283844] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Porphobilinogen deaminase is the third enzyme in the heme biosynthetic pathway. hem3 mutants in Saccharomyces cerevisiae are deficient in porphobilinogen deaminase activity. We have isolated the HEM3 gene by complementation of the heme auxotrophy of a hem3 mutant. Sequence analysis reveals an open reading frame of 981 nucleotides. The derived amino acid sequence of the protein encoded by HEM3 shows extensive homology to the reported sequences for porphobilinogen deaminase from a number of other sources, indicating that HEM3 is the structural gene for porphobilinogen deaminase. Earlier reports have suggested that expression of HEM3 is induced by porphobilinogen, the substrate of the encoded enzyme. We have investigated the transcription of HEM3 and have found that it is not affected by the ability of the cell to make porphobilinogen or heme. However, we have found that HAP2 and HAP3 gene products are involved in the expression of HEM3. An important element required for expression of HEM3 has been localized to a small region that contains a sequence homologous to the HAP2-3-4 binding sites of several genes including HEM1. These findings suggest that HEM3 expression is regulated in the same manner as that of HEM1 which encodes the first enzyme of the heme biosynthetic pathway.
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Affiliation(s)
- T Keng
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
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Jordan PM, Warren MJ, Mgbeje BI, Wood SP, Cooper JB, Louie G, Brownlie P, Lambert R, Blundell TL. Crystallization and preliminary X-ray investigation of Escherichia coli porphobilinogen deaminase. J Mol Biol 1992; 224:269-71. [PMID: 1548705 DOI: 10.1016/0022-2836(92)90590-g] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Porphobilinogen deaminase, the polymerase that catalyses the synthesis of preuroporphyrinogen, the linear tetrapyrrole precursor of uroporphyrinogen III, has been crystallized from sodium acetate buffer with polyethylene glycol 6000 as precipitant. The crystals are orthorhombic and the space group is P2(1)2(1)2, with unit cell dimensions a = 88.01 A, b = 75.86 A, c = 50.53 A and alpha = beta = gamma = 90 degrees, indicating a single molecule of 34 kDa in the asymmetric unit. The crystals grow to dimensions of 1 mm x 2 mm x 0.5 mm within two weeks in the dark and are stable in the X-ray beam for at least 40 hours. Diffraction data beyond 1.7 A resolution, observed with a synchrotron radiation source, indicate that a high resolution structure analysis is feasible.
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Affiliation(s)
- P M Jordan
- School of Biological Sciences, Queen Mary and Westfield College, London, U.K
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28
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Jordan PM, Woodcock SC. Mutagenesis of arginine residues in the catalytic cleft of Escherichia coli porphobilinogen deaminase that affects dipyrromethane cofactor assembly and tetrapyrrole chain initiation and elongation. Biochem J 1991; 280 ( Pt 2):445-9. [PMID: 1747120 PMCID: PMC1130568 DOI: 10.1042/bj2800445] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Substitutions of conserved arginine residues in the catalytic cleft of Escherichia coli porphobilinogen deaminase were constructed by site-specific mutagenesis of the hemC gene. Mutant proteins exhibited a range of defects including the failure to assemble the dipyrromethane cofactor and the inability to initiate and propagate the tetrapolymerization reaction. Mutations of arginine residues at positions 11, 131, 132 and 155, all of which interact with the carboxylic acid side chains of the dipyrromethane cofactor, were the most disruptive.
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Affiliation(s)
- P M Jordan
- School of Biological Sciences, Queen Mary College, University of London, U.K
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Jordan PM. Chapter 1 The biosynthesis of 5-aminolaevulinic acid and its transformation into uroporphyrinogen III. BIOSYNTHESIS OF TETRAPYRROLES 1991. [DOI: 10.1016/s0167-7306(08)60108-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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31
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Aplin RT, Baldwin JE, Pichon C, Roessner CA, Ian Scott A, Schofield CJ, Stolowich NJ, Warren MJ. Observation of enzyme bound intermediates in the biosynthesis of preuroporphyrinogen by PBG deaminase. Bioorg Med Chem Lett 1991. [DOI: 10.1016/s0960-894x(01)80453-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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32
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Warren MJ, Scott AI. Tetrapyrrole assembly and modification into the ligands of biologically functional cofactors. Trends Biochem Sci 1990; 15:486-91. [PMID: 2077690 DOI: 10.1016/0968-0004(90)90304-t] [Citation(s) in RCA: 98] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Data obtained using a combination of molecular biology and NMR spectroscopy has transformed our thinking about the evolution of the biochemical machinery required for the synthesis of the vital metallopigments: haem, chlorophyll, vitamin B12 and factor F430. One of the most recent advances is the discovery of a unique dipyrromethane cofactor that is bound covalently at the active site of porphobillinogen deaminase, the key enzyme of tetrapyrrole assembly. We will also discuss how the oxidation level and chromophoric arrangement of the uroporphinoid ring, rather than its substitution pattern, provides the necessary molecular recognition for some of the later enzymes, whose function is to decorate the template by C-methylation on the way to the biologically active cofactors.
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Affiliation(s)
- M J Warren
- Department of Chemistry, Texas A and M University, College Station 77843-3255
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