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Koch AA, Schmidt JJ, Lowell AN, Hansen DA, Coburn KM, Chemler JA, Sherman DH. Probing Selectivity and Creating Structural Diversity Through Hybrid Polyketide Synthases. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202004991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Aaron A. Koch
- Life Sciences Institute The University of Michigan (USA) 210 Washtenaw Avenue Ann Arbor MI 48109-2216 USA
| | - Jennifer J. Schmidt
- Life Sciences Institute The University of Michigan (USA) 210 Washtenaw Avenue Ann Arbor MI 48109-2216 USA
| | - Andrew N. Lowell
- Life Sciences Institute The University of Michigan (USA) 210 Washtenaw Avenue Ann Arbor MI 48109-2216 USA
- Current address: Department of Chemistry Virginia Tech Blacksburg VA 24061 USA
| | - Douglas A. Hansen
- Life Sciences Institute The University of Michigan (USA) 210 Washtenaw Avenue Ann Arbor MI 48109-2216 USA
| | - Katherine M. Coburn
- Life Sciences Institute The University of Michigan (USA) 210 Washtenaw Avenue Ann Arbor MI 48109-2216 USA
| | - Joseph A. Chemler
- Life Sciences Institute The University of Michigan (USA) 210 Washtenaw Avenue Ann Arbor MI 48109-2216 USA
| | - David H. Sherman
- Life Sciences Institute The University of Michigan (USA) 210 Washtenaw Avenue Ann Arbor MI 48109-2216 USA
- Departments of Medicinal Chemistry, Chemistry, Microbiology & Immunology The University of Michigan USA
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Koch AA, Schmidt JJ, Lowell AN, Hansen DA, Coburn KM, Chemler JA, Sherman DH. Probing Selectivity and Creating Structural Diversity Through Hybrid Polyketide Synthases. Angew Chem Int Ed Engl 2020; 59:13575-13580. [PMID: 32357274 DOI: 10.1002/anie.202004991] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Indexed: 11/09/2022]
Abstract
Engineering polyketide synthases (PKS) to produce new metabolites requires an understanding of catalytic points of failure during substrate processing. Growing evidence indicates the thioesterase (TE) domain as a significant bottleneck within engineered PKS systems. We created a series of hybrid PKS modules bearing exchanged TE domains from heterologous pathways and challenged them with both native and non-native polyketide substrates. Reactions pairing wildtype PKS modules with non-native substrates primarily resulted in poor conversions to anticipated macrolactones. Likewise, product formation with native substrates and hybrid PKS modules bearing non-cognate TE domains was severely reduced. In contrast, non-native substrates were converted by most hybrid modules containing a substrate compatible TE, directly implicating this domain as the major catalytic gatekeeper and highlighting its value as a target for protein engineering to improve analog production in PKS pathways.
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Affiliation(s)
- Aaron A Koch
- Life Sciences Institute, The University of Michigan (USA), 210 Washtenaw Avenue, Ann Arbor, MI, 48109-2216, USA
| | - Jennifer J Schmidt
- Life Sciences Institute, The University of Michigan (USA), 210 Washtenaw Avenue, Ann Arbor, MI, 48109-2216, USA
| | - Andrew N Lowell
- Life Sciences Institute, The University of Michigan (USA), 210 Washtenaw Avenue, Ann Arbor, MI, 48109-2216, USA.,Current address: Department of Chemistry, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Douglas A Hansen
- Life Sciences Institute, The University of Michigan (USA), 210 Washtenaw Avenue, Ann Arbor, MI, 48109-2216, USA
| | - Katherine M Coburn
- Life Sciences Institute, The University of Michigan (USA), 210 Washtenaw Avenue, Ann Arbor, MI, 48109-2216, USA
| | - Joseph A Chemler
- Life Sciences Institute, The University of Michigan (USA), 210 Washtenaw Avenue, Ann Arbor, MI, 48109-2216, USA
| | - David H Sherman
- Life Sciences Institute, The University of Michigan (USA), 210 Washtenaw Avenue, Ann Arbor, MI, 48109-2216, USA.,Departments of Medicinal Chemistry, Chemistry, Microbiology & Immunology, The University of Michigan, USA
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Ratnayake AS, Chang LP, Tumey LN, Loganzo F, Chemler JA, Wagenaar M, Musto S, Li F, Janso JE, Ballard TE, Rago B, Steele GL, Ding W, Feng X, Hosselet C, Buklan V, Lucas J, Koehn FE, O'Donnell CJ, Graziani EI. Natural Product Bis-Intercalator Depsipeptides as a New Class of Payloads for Antibody-Drug Conjugates. Bioconjug Chem 2018; 30:200-209. [PMID: 30543418 DOI: 10.1021/acs.bioconjchem.8b00843] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A potent class of DNA-damaging agents, natural product bis-intercalator depsipeptides (NPBIDs), was evaluated as ultrapotent payloads for use in antibody-drug conjugates (ADCs). Detailed investigation of potency (both in cells and via biophysical characterization of DNA binding), chemical tractability, and in vitro and in vivo stability of the compounds in this class eliminated a number of potential candidates, greatly reducing the complexity and resources required for conjugate preparation and evaluation. This effort yielded a potent, stable, and efficacious ADC, PF-06888667, consisting of the bis-intercalator, SW-163D, conjugated via an N-acetyl-lysine-valine-citrulline- p-aminobenzyl alcohol- N, N-dimethylethylenediamine (AcLysValCit-PABC-DMAE) linker to an engineered variant of the anti-Her2 mAb, trastuzumab, catalyzed by transglutaminase.
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Affiliation(s)
- Anokha S Ratnayake
- Medicine Design , Pfizer Worldwide Research and Development , 445 Eastern Point Road , Groton , Connecticut 06340 , United States
| | - Li-Ping Chang
- Medicine Design , Pfizer Worldwide Research and Development , 445 Eastern Point Road , Groton , Connecticut 06340 , United States
| | - L Nathan Tumey
- Medicine Design , Pfizer Worldwide Research and Development , 445 Eastern Point Road , Groton , Connecticut 06340 , United States
| | - Frank Loganzo
- Oncology Research , Pfizer Worldwide Research and Development , 401 North Middletown Road , Pearl River , New York 10965 , United States
| | - Joseph A Chemler
- Medicine Design , Pfizer Worldwide Research and Development , 445 Eastern Point Road , Groton , Connecticut 06340 , United States
| | - Melissa Wagenaar
- Medicine Design , Pfizer Worldwide Research and Development , 445 Eastern Point Road , Groton , Connecticut 06340 , United States
| | - Sylvia Musto
- Oncology Research , Pfizer Worldwide Research and Development , 401 North Middletown Road , Pearl River , New York 10965 , United States
| | - Fengping Li
- Medicine Design , Pfizer Worldwide Research and Development , 445 Eastern Point Road , Groton , Connecticut 06340 , United States
| | - Jeffrey E Janso
- Medicine Design , Pfizer Worldwide Research and Development , 445 Eastern Point Road , Groton , Connecticut 06340 , United States
| | - T Eric Ballard
- Medicine Design , Pfizer Worldwide Research and Development , 445 Eastern Point Road , Groton , Connecticut 06340 , United States
| | - Brian Rago
- Medicine Design , Pfizer Worldwide Research and Development , 445 Eastern Point Road , Groton , Connecticut 06340 , United States
| | - Greg L Steele
- Medicine Design , Pfizer Worldwide Research and Development , 445 Eastern Point Road , Groton , Connecticut 06340 , United States
| | - WeiDong Ding
- Medicine Design , Pfizer Worldwide Research and Development , 445 Eastern Point Road , Groton , Connecticut 06340 , United States
| | - Xidong Feng
- Medicine Design , Pfizer Worldwide Research and Development , 445 Eastern Point Road , Groton , Connecticut 06340 , United States
| | - Christine Hosselet
- Oncology Research , Pfizer Worldwide Research and Development , 401 North Middletown Road , Pearl River , New York 10965 , United States
| | - Vlad Buklan
- Oncology Research , Pfizer Worldwide Research and Development , 401 North Middletown Road , Pearl River , New York 10965 , United States
| | - Judy Lucas
- Oncology Research , Pfizer Worldwide Research and Development , 401 North Middletown Road , Pearl River , New York 10965 , United States
| | - Frank E Koehn
- Medicine Design , Pfizer Worldwide Research and Development , 445 Eastern Point Road , Groton , Connecticut 06340 , United States
| | - Christopher J O'Donnell
- Medicine Design , Pfizer Worldwide Research and Development , 445 Eastern Point Road , Groton , Connecticut 06340 , United States
| | - Edmund I Graziani
- Medicine Design , Pfizer Worldwide Research and Development , 445 Eastern Point Road , Groton , Connecticut 06340 , United States
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McDonnell KJ, Chemler JA, Bartels PL, O'Brien E, Marvin ML, Ortega J, Stern RH, Raskin L, Li GM, Sherman DH, Barton JK, Gruber SB. A human MUTYH variant linking colonic polyposis to redox degradation of the [4Fe4S] 2+ cluster. Nat Chem 2018; 10:873-880. [PMID: 29915346 DOI: 10.1038/s41557-018-0068-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Accepted: 04/20/2018] [Indexed: 12/26/2022]
Abstract
The human DNA repair enzyme MUTYH excises mispaired adenine residues in oxidized DNA. Homozygous MUTYH mutations underlie the autosomal, recessive cancer syndrome MUTYH-associated polyposis. We report a MUTYH variant, p.C306W (c.918C>G), with a tryptophan residue in place of native cysteine, that ligates the [4Fe4S] cluster in a patient with colonic polyposis and family history of early age colon cancer. In bacterial MutY, the [4Fe4S] cluster is redox active, allowing rapid localization to target lesions by long-range, DNA-mediated signalling. In the current study, using DNA electrochemistry, we determine that wild-type MUTYH is similarly redox-active, but MUTYH C306W undergoes rapid oxidative degradation of its cluster to [3Fe4S]+, with loss of redox signalling. In MUTYH C306W, oxidative cluster degradation leads to decreased DNA binding and enzyme function. This study confirms redox activity in eukaryotic DNA repair proteins and establishes MUTYH C306W as a pathogenic variant, highlighting the essential role of redox signalling by the [4Fe4S] cluster.
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Affiliation(s)
- Kevin J McDonnell
- University of Southern California Norris Comprehensive Cancer Center, Los Angeles, CA, USA
| | - Joseph A Chemler
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Phillip L Bartels
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Elizabeth O'Brien
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Monica L Marvin
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Janice Ortega
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Ralph H Stern
- Division of Molecular Medicine and Genetics, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | | | - Guo-Min Li
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - David H Sherman
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA. .,Departments of Medicinal Chemistry, Chemistry and Microbiology & Immunology, University of Michigan, Ann Arbor, MI, USA.
| | - Jacqueline K Barton
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA.
| | - Stephen B Gruber
- University of Southern California Norris Comprehensive Cancer Center, Los Angeles, CA, USA.
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Lowell AN, DeMars MD, Slocum ST, Yu F, Anand K, Chemler JA, Korakavi N, Priessnitz JK, Park SR, Koch AA, Schultz PJ, Sherman DH. Chemoenzymatic Total Synthesis and Structural Diversification of Tylactone-Based Macrolide Antibiotics through Late-Stage Polyketide Assembly, Tailoring, and C-H Functionalization. J Am Chem Soc 2017; 139:7913-7920. [PMID: 28525276 PMCID: PMC5532807 DOI: 10.1021/jacs.7b02875] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Polyketide synthases (PKSs) represent a powerful catalytic platform capable of effecting multiple carbon-carbon bond forming reactions and oxidation state adjustments. We explored the functionality of two terminal PKS modules that produce the 16-membered tylosin macrocycle, using them as biocatalysts in the chemoenzymatic synthesis of tylactone and its subsequent elaboration to complete the first total synthesis of the juvenimicin, M-4365, and rosamicin classes of macrolide antibiotics via late-stage diversification. Synthetic chemistry was employed to generate the tylactone hexaketide chain elongation intermediate that was accepted by the juvenimicin (Juv) ketosynthase of the penultimate JuvEIV PKS module. The hexaketide is processed through two complete modules (JuvEIV and JuvEV) in vitro, which catalyze elongation and functionalization of two ketide units followed by cyclization of the resulting octaketide into tylactone. After macrolactonization, a combination of in vivo glycosylation, selective in vitro cytochrome P450-mediated oxidation, and chemical oxidation was used to complete the scalable construction of a series of macrolide natural products in as few as 15 linear steps (21 total) with an overall yield of 4.6%.
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Affiliation(s)
- Andrew N. Lowell
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Matthew D. DeMars
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Samuel T. Slocum
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Fengan Yu
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Krithika Anand
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Joseph A. Chemler
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Nisha Korakavi
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Jennifer K. Priessnitz
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Sung Ryeol Park
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Aaron A. Koch
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Pamela J. Schultz
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - David H. Sherman
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Microbiology & Immunology, University of Michigan, Ann Arbor, Michigan 48109, United States
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Koryakina I, Kasey C, McArthur JB, Lowell AN, Chemler JA, Li S, Hansen DA, Sherman DH, Williams GJ. Inversion of Extender Unit Selectivity in the Erythromycin Polyketide Synthase by Acyltransferase Domain Engineering. ACS Chem Biol 2017; 12:114-123. [PMID: 28103677 DOI: 10.1021/acschembio.6b00732] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Acyltransferase (AT) domains of polyketide synthases (PKSs) select extender units for incorporation into polyketides and dictate large portions of the structures of clinically relevant natural products. Accordingly, there is significant interest in engineering the substrate specificity of PKS ATs in order to site-selectively manipulate polyketide structure. However, previous attempts to engineer ATs have yielded mutant PKSs with relaxed extender unit specificity, rather than an inversion of selectivity from one substrate to another. Here, by directly screening the extender unit selectivity of mutants from active site saturation libraries of an AT from the prototypical PKS, 6-deoxyerythronolide B synthase, a set of single amino acid substitutions was discovered that dramatically impact the selectivity of the PKS with only modest reductions of product yields. One particular substitution (Tyr189Arg) inverted the selectivity of the wild-type PKS from its natural substrate toward a non-natural alkynyl-modified extender unit while maintaining more than twice the activity of the wild-type PKS with its natural substrate. The strategy and mutations described herein form a platform for combinatorial biosynthesis of site-selectively modified polyketide analogues that are modified with non-natural and non-native chemical functionality.
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Affiliation(s)
- Irina Koryakina
- Department
of Chemistry, NC State University, Raleigh, North Carolina 27695-8204, United States
| | - Christian Kasey
- Department
of Chemistry, NC State University, Raleigh, North Carolina 27695-8204, United States
| | | | - Andrew N. Lowell
- Life
Sciences Institute, Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Joseph A. Chemler
- Life
Sciences Institute, Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Shasha Li
- Life
Sciences Institute, Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Douglas A. Hansen
- Life
Sciences Institute, Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - David H. Sherman
- Life
Sciences Institute, Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Chemistry, Department of Microbiology & Immunology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Gavin J. Williams
- Department
of Chemistry, NC State University, Raleigh, North Carolina 27695-8204, United States
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Chemler JA, Tripathi A, Hansen DA, O'Neil-Johnson M, Williams RB, Starks C, Park SR, Sherman DH. Evolution of Efficient Modular Polyketide Synthases by Homologous Recombination. J Am Chem Soc 2015; 137:10603-9. [PMID: 26230368 DOI: 10.1021/jacs.5b04842] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The structural scaffolds of many complex natural products are produced by multifunctional type I polyketide synthase (PKS) enzymes that operate as biosynthetic assembly lines. The modular nature of these mega-enzymes presents an opportunity to construct custom biocatalysts built in a lego-like fashion by inserting, deleting, or exchanging native or foreign domains to produce targeted variants of natural polyketides. However, previously engineered PKS enzymes are often impaired resulting in limited production compared to native systems. Here, we show a versatile method for generating and identifying functional chimeric PKS enzymes for synthesizing custom macrolactones and macrolides. PKS genes from the pikromycin and erythromycin pathways were hybridized in Saccharomyces cerevisiae to generate hybrid libraries. We used a 96-well plate format for plasmid purification, transformations, sequencing, protein expression, in vitro reactions and analysis of metabolite formation. Active chimeric enzymes were identified with new functionality. Streptomyces venezuelae strains that expressed these PKS chimeras were capable of producing engineered macrolactones. Furthermore, a macrolactone generated from selected PKS chimeras was fully functionalized into a novel macrolide analogue. This method permits the engineering of PKS pathways as modular building blocks for the production of new antibiotic-like molecules.
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Affiliation(s)
| | | | | | - Mark O'Neil-Johnson
- Sequoia Sciences, Inc. , 1912 Innerbelt Business Center Drive, Saint Louis, Missouri 63114, United States
| | - Russell B Williams
- Sequoia Sciences, Inc. , 1912 Innerbelt Business Center Drive, Saint Louis, Missouri 63114, United States
| | - Courtney Starks
- Sequoia Sciences, Inc. , 1912 Innerbelt Business Center Drive, Saint Louis, Missouri 63114, United States
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McDonnell K, Chemler JA, Marvin ML, Stern RH, Raskin L, Sherman DH, Gruber SB. Characterization of a Novel Human MUTYH Variant Causing Colonic Polyposis through Disruption of the Fe-S Cluster. J Clin Oncol 2015. [DOI: 10.1200/jco.2015.33.15_suppl.e12514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Kevin McDonnell
- University of Southern California Norris Comprehensive Cancer Center, Los Angeles, CA
| | | | - Monica L. Marvin
- Department of Internal Medicine and Department of Human Genetics, University of Michigan, Ann Arbor, MI
| | - Ralph H. Stern
- Department of Internal Medicine, Molecular Medicine and Genetics; University of Michigan, Ann Arbor, MI
| | - Leon Raskin
- Vanderbilt-Ingram Cancer Center, Nashville, TN
| | | | - Stephen B. Gruber
- University of Southern California Norris Comprehensive Cancer Center, Los Angeles, CA
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McDonnell K, Chemler JA, Marvin ML, Stern RH, Raskin L, Sherman DH, Gruber SB. Identification and functional characterization of a novel MUTYH gene mutation. J Clin Oncol 2012. [DOI: 10.1200/jco.2012.30.15_suppl.e12026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
e12026 Background: Biallelic germline mutations in MUTYH result in the autosomal recessive syndrome of MUTYH associated polyposis (MAP).Three well-known, common mutations account for the vast majority of identifiable germline mutations, and serve as the basis for current genetic testing strategies. Comprehensive sequencing of MUTYH often identifies variants of uncertain pathologic significance, and studies to determine the pathogenicity of newly identified variants may offer valuable clinical information and mechanistic insights. In the present study we seek to describe the base-excision repair function of a novel MUTYH (p.C306W) mutation identified in a patient with multiple colon polyps and a family history of colon cancers. Methods: A 50 year old patient with >50 adenomas underwent clinical and laboratory evaluation to assess for germline genetic mutations. We performed Sanger sequencing of tumor and germline DNA together with targeted restriction enzyme digest of germline DNA and fragment DNA sequencing of the alleles. We prepared MUTYH proteins with protein liquid chromatography and assessed their mismatched adenine excision repair capacity employing a glycosylase assay. Results: Analysis of the patient's germline DNA revealed an absence of APC mutations, and the presence of the previously well characterized p.G396D MUTYH mutation as well as a novel p.C306W mutation. Targeted restriction enzyme digest demonstrated trans configuration of the p.G396D and p.C306W MUTYH mutations. Mismatched adenine excision functionality of wildtype MUTYH, known mutant controls p.G396D and p.Y179C, and putative mutant p.C306W were assessed in the glycosylase assay. Consistent with previous experimental observations, relative to wildtype MUTYH, the p.G396D and p.Y179C MUTYH mutants demonstrated attenuated adenine excision activities of 43% and 0%, respectively. Comparable to the activity of the pY179C mutant, the novel p.C306D mutant demonstrated 0% adenine excision activity. Subsequent tumor analysis demonstrated G:C to T:A transversion in the APC gene in somatic DNA derived from an adenoma. Conclusions: Experimental and clinical data demonstrate that p.C306D MUTYH is a pathogenic mutation contributing to the phenotype of MAP.
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Affiliation(s)
- Kevin McDonnell
- Department of Internal Medicine, Division of Hematology/Oncology, University of Michigan, Ann Arbor, MI
| | | | - Monica L. Marvin
- Department of Internal Medicine and Department of Human Genetics, University of Michigan, Ann Arbor, MI
| | - Ralph H. Stern
- Department of Internal Medicine, Molecular Medicine and Genetics; University of Michigan, Ann Arbor, MI
| | - Leon Raskin
- Department of Preventive Medicine, University of Southern California, Los Angeles, CA
| | | | - Stephen B. Gruber
- USC Norris Comprehensive Cancer Center, Keck School of Medicine, Los Angeles, CA
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Chemler JA, Buchholz TJ, Geders TW, Akey DL, Rath CM, Chlipala GE, Smith JL, Sherman DH. Biochemical and structural characterization of germicidin synthase: analysis of a type III polyketide synthase that employs acyl-ACP as a starter unit donor. J Am Chem Soc 2012; 134:7359-66. [PMID: 22480290 DOI: 10.1021/ja2112228] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Germicidin synthase (Gcs) from Streptomyces coelicolor is a type III polyketide synthase (PKS) with broad substrate flexibility for acyl groups linked through a thioester bond to either coenzyme A (CoA) or acyl carrier protein (ACP). Germicidin synthesis was reconstituted in vitro by coupling Gcs with fatty acid biosynthesis. Since Gcs has broad substrate flexibility, we directly compared the kinetic properties of Gcs with both acyl-ACP and acyl-CoA. The catalytic efficiency of Gcs for acyl-ACP was 10-fold higher than for acyl-CoA, suggesting a strong preference toward carrier protein starter unit transfer. The 2.9 Å germicidin synthase crystal structure revealed canonical type III PKS architecture along with an unusual helical bundle of unknown function that appears to extend the dimerization interface. A pair of arginine residues adjacent to the active site affect catalytic activity but not ACP binding. This investigation provides new and surprising information about the interactions between type III PKSs and ACPs that will facilitate the construction of engineered systems for production of novel polyketides.
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Affiliation(s)
- Joseph A Chemler
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, USA
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11
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Bonnett SA, Rath CM, Shareef AR, Joels JR, Chemler JA, Håkansson K, Reynolds K, Sherman DH. Acyl-CoA subunit selectivity in the pikromycin polyketide synthase PikAIV: steady-state kinetics and active-site occupancy analysis by FTICR-MS. ACTA ACUST UNITED AC 2012; 18:1075-81. [PMID: 21944746 DOI: 10.1016/j.chembiol.2011.07.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2011] [Revised: 06/23/2011] [Accepted: 07/04/2011] [Indexed: 10/17/2022]
Abstract
Polyketide natural products generated by type I modular polyketide synthases (PKSs) are vital components in our drug repertoire. To reprogram these biosynthetic assembly lines, we must first understand the steps that occur within the modular "black boxes." Herein, key steps of acyl-CoA extender unit selection are explored by in vitro biochemical analysis of the PikAIV PKS model system. Two complementary approaches are employed: a fluorescent-probe assay for steady-state kinetic analysis, and Fourier Transform Ion Cyclotron Resonance-mass spectrometry (FTICR-MS) to monitor active-site occupancy. Findings from five enzyme variants and four model substrates have enabled a model to be proposed involving catalysis based upon acyl-CoA substrate loading followed by differential rates of hydrolysis. These efforts suggest a strategy for future pathway engineering efforts using unnatural extender units with slow rates of hydrolytic off-loading from the acyltransferase domain.
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Affiliation(s)
- Shilah A Bonnett
- Department of Chemistry, Portland State University, Portland, OR 97201, USA
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12
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Chemler JA, Lim CG, Daiss JL, Koffas MAG. A versatile microbial system for biosynthesis of novel polyphenols with altered estrogen receptor binding activity. Chem Biol 2010; 17:392-401. [PMID: 20416510 DOI: 10.1016/j.chembiol.2010.03.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Revised: 03/20/2010] [Accepted: 03/24/2010] [Indexed: 11/30/2022]
Abstract
Isoflavonoids possess enormous potential for human health with potential impact on heart disease and cancer, and some display striking affinities for steroid receptors. Synthesized primarily by legumes, isoflavonoids are present in low and variable abundance within complex mixtures, complicating efforts to assess their clinical potential. To satisfy the need for controlled, efficient, and flexible biosynthesis of isoflavonoids, a three-enzyme system has been constructed in yeast that can convert natural and synthetic flavanones into their corresponding isoflavones in practical quantities. Based on the determination of the substrate requirements of isoflavone synthase, a series of natural and nonnatural isoflavones were prepared and their binding affinities for the human estrogen receptors (ER alpha and ER beta) were determined. Structure activity relationships are suggested based on changes to binding affinities related to small variations on the isoflavone structure.
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Affiliation(s)
- Joseph A Chemler
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
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Chemler JA, Koffas MAG. Metabolic engineering for plant natural product biosynthesis in microbes. Curr Opin Biotechnol 2008; 19:597-605. [DOI: 10.1016/j.copbio.2008.10.011] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Revised: 10/21/2008] [Accepted: 10/23/2008] [Indexed: 11/28/2022]
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Abstract
Flavonoids are plant secondary metabolites often used as nutraceutical supplements, but a growing number of unnatural flavonoids are being investigated as therapeutic agents. Cultures of Saccharomyces cerevisiae expressing recombinant flavonoid enzymes, including 4-coumaroyl:CoA ligase (4CL), chalcone synthase (CHS), chalcone isomerase (CHI), and flavanone 3beta-hydroxylase (FHT), produced novel flavanones and dihydroflavonols when fed with a number of aromatic acrylic acids. The flavonoid network also exhibited broad substrate specificity by converting muconic acid into a unique polypropanoid.
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Affiliation(s)
- Joseph A Chemler
- State University of New York at Buffalo, Department of Chemical and Biological Engineering, 303 Furnas Hall, Buffalo, NY 14260, USA
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Chemler JA, Yan Y, Koffas MAG. Biosynthesis of isoprenoids, polyunsaturated fatty acids and flavonoids in Saccharomyces cerevisiae. Microb Cell Fact 2006; 5:20. [PMID: 16719921 PMCID: PMC1533850 DOI: 10.1186/1475-2859-5-20] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2006] [Accepted: 05/23/2006] [Indexed: 11/10/2022] Open
Abstract
Industrial biotechnology employs the controlled use of microorganisms for the production of synthetic chemicals or simple biomass that can further be used in a diverse array of applications that span the pharmaceutical, chemical and nutraceutical industries. Recent advances in metagenomics and in the incorporation of entire biosynthetic pathways into Saccharomyces cerevisiae have greatly expanded both the fitness and the repertoire of biochemicals that can be synthesized from this popular microorganism. Further, the availability of the S. cerevisiae entire genome sequence allows the application of systems biology approaches for improving its enormous biosynthetic potential. In this review, we will describe some of the efforts on using S. cerevisiae as a cell factory for the biosynthesis of high-value natural products that belong to the families of isoprenoids, flavonoids and long chain polyunsaturated fatty acids. As natural products are increasingly becoming the center of attention of the pharmaceutical and nutraceutical industries, the use of S. cerevisiae for their production is only expected to expand in the future, further allowing the biosynthesis of novel molecular structures with unique properties.
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Affiliation(s)
- Joseph A Chemler
- Department of Chemical and Biological Engineering, State University of New York at Buffalo, Buffalo, NY 14260-4200, USA
| | - Yajun Yan
- Department of Chemical and Biological Engineering, State University of New York at Buffalo, Buffalo, NY 14260-4200, USA
| | - Mattheos AG Koffas
- Department of Chemical and Biological Engineering, State University of New York at Buffalo, Buffalo, NY 14260-4200, USA
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