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Budimir ZL, Patel RS, Eggly A, Evans CN, Rondon-Cordero HM, Adams JJ, Das C, Parkinson EI. Biocatalytic cyclization of small macrolactams by a penicillin-binding protein-type thioesterase. Nat Chem Biol 2024; 20:120-128. [PMID: 38062262 PMCID: PMC10999230 DOI: 10.1038/s41589-023-01495-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [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] [Received: 05/10/2023] [Accepted: 11/01/2023] [Indexed: 12/17/2023]
Abstract
Macrocyclic peptides represent promising scaffolds for chemical tools and potential therapeutics. Synthetic methods for peptide macrocyclization are often hampered by C-terminal epimerization and oligomerization, leading to difficult scalability. While chemical strategies to circumvent this issue exist, they often require specific amino acids to be present in the peptide sequence. Herein, we report the characterization of Ulm16, a peptide cyclase belonging to the penicillin-binding protein-type class of thioesterases that catalyze head-to-tail macrolactamization of nonribosmal peptides. Ulm16 efficiently cyclizes various nonnative peptides ranging from 4 to 6 amino acids with catalytic efficiencies of up to 3 × 106 M-1 s-1. Unlike many previously described homologs, Ulm16 tolerates a variety of C- and N-terminal amino acids. The crystal structure of Ulm16, along with modeling of its substrates and site-directed mutagenesis, allows for rationalization of this wide substrate scope. Overall, Ulm16 represents a promising tool for the biocatalytic production of macrocyclic peptides.
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Affiliation(s)
| | - Rishi S Patel
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - Alyssa Eggly
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - Claudia N Evans
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | | | - Jessica J Adams
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - Chittaranjan Das
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - Elizabeth I Parkinson
- Department of Chemistry, Purdue University, West Lafayette, IN, USA.
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, USA.
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Lester A, Sandman M, Herring C, Girard C, Dixon B, Ramsdell H, Reber C, Poulos J, Mitchell A, Spinney A, Henager ME, Evans CN, Turlington M, Johnson QR. Computational Exploration of Potential CFTR Binding Sites for Type I Corrector Drugs. Biochemistry 2023; 62:2503-2515. [PMID: 37437308 PMCID: PMC10433520 DOI: 10.1021/acs.biochem.3c00165] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [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] [Received: 03/24/2023] [Revised: 06/22/2023] [Indexed: 07/14/2023]
Abstract
Cystic fibrosis (CF) is a recessive genetic disease that is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) protein. The recent development of a class of drugs called "correctors", which repair the structure and function of mutant CFTR, has greatly enhanced the life expectancy of CF patients. These correctors target the most common disease causing CFTR mutant F508del and are exemplified by the FDA-approved VX-809. While one binding site of VX-809 to CFTR was recently elucidated by cryo-electron microscopy, four additional binding sites have been proposed in the literature and it has been theorized that VX-809 and structurally similar correctors may engage multiple CFTR binding sites. To explore these five binding sites, ensemble docking was performed on wild-type CFTR and the F508del mutant using a large library of structurally similar corrector drugs, including VX-809 (lumacaftor), VX-661 (tezacaftor), ABBV-2222 (galicaftor), and a host of other structurally related molecules. For wild-type CFTR, we find that only one site, located in membrane spanning domain 1 (MSD1), binds favorably to our ligand library. While this MSD1 site also binds our ligand library for F508del-CFTR, the F508del mutation also opens a binding site in nucleotide binding domain 1 (NBD1), which enables strong binding of our ligand library to this site. This NBD1 site in F508del-CFTR exhibits the strongest overall binding affinity for our library of corrector drugs. This data may serve to better understand the structural changes induced by mutation of CFTR and how correctors bind to the protein. Additionally, it may aid in the design of new, more effective CFTR corrector drugs.
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Affiliation(s)
- Anna Lester
- Berry College Department
of Chemistry and Biochemistry, Mount Berry, Georgia 30149, United States
| | - Madeline Sandman
- Berry College Department
of Chemistry and Biochemistry, Mount Berry, Georgia 30149, United States
| | - Caitlin Herring
- Berry College Department
of Chemistry and Biochemistry, Mount Berry, Georgia 30149, United States
| | - Christian Girard
- Berry College Department
of Chemistry and Biochemistry, Mount Berry, Georgia 30149, United States
| | - Brandon Dixon
- Berry College Department
of Chemistry and Biochemistry, Mount Berry, Georgia 30149, United States
| | - Havanna Ramsdell
- Berry College Department
of Chemistry and Biochemistry, Mount Berry, Georgia 30149, United States
| | - Callista Reber
- Berry College Department
of Chemistry and Biochemistry, Mount Berry, Georgia 30149, United States
| | - Jack Poulos
- Berry College Department
of Chemistry and Biochemistry, Mount Berry, Georgia 30149, United States
| | - Alexis Mitchell
- Berry College Department
of Chemistry and Biochemistry, Mount Berry, Georgia 30149, United States
| | - Allison Spinney
- Berry College Department
of Chemistry and Biochemistry, Mount Berry, Georgia 30149, United States
| | - Marissa E. Henager
- Berry College Department
of Chemistry and Biochemistry, Mount Berry, Georgia 30149, United States
| | - Claudia N. Evans
- Berry College Department
of Chemistry and Biochemistry, Mount Berry, Georgia 30149, United States
| | - Mark Turlington
- Berry College Department
of Chemistry and Biochemistry, Mount Berry, Georgia 30149, United States
| | - Quentin R. Johnson
- Berry College Department
of Chemistry and Biochemistry, Mount Berry, Georgia 30149, United States
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Abstract
Total serum triiodothyronine (T3) and thyroxine (T4) concentrations were assayed in neonatal llamas from birth to 90 days of age. T3 concentrations were high at birth and increased from birth to approximately 6 days, then gradually decreased. T4 concentrations were highest at time of birth and decreased gradually over the 90-day period.
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Affiliation(s)
- B G McLaughlin
- Department of Pathology, Murray State University Breathitt Veterinary Center, Hopkinsville, KY 42240
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Affiliation(s)
- B G McLaughlin
- Department of Pathology, Breathitt Veterinary Center, Murray State University, Hopkinsville, KY 42240
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McLaughlin BG, Evans CN, McLaughlin PS, Johnson LW, Smith AR, Zachary JF. An Eperythrozoon-like parasite in llamas. J Am Vet Med Assoc 1990; 197:1170-5. [PMID: 2254144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
An Eperythrozoon-like RBC parasite was found in a herd of llamas in western Kentucky. The light microscopic and electron microscopic features of the organism were similar to those of E suis. Results of an indirect hemagglutination test for E suis were positive with sera from some parasitemic and nonparasitemic llamas. Parasitemic llamas were usually less than 1 year old and had more severe clinical signs of disease than did older llamas. Poor weight gain and growth, anorexia, and prolonged recumbency were the principal signs of disease. Anemia was usually mild and not accompanied by icterus. Hypoglycemia was associated with parasitemia. Some response to oral or parenteral treatment with tetracycline was noticed, but recrudescence of the infection in some treated llamas was observed. Llamas in nearly every region of the United States have had titers in approximately 12% of samples tested, suggesting that infection with the organism may be widespread. Parasitemic llamas have been recognized in at least 8 states.
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Affiliation(s)
- B G McLaughlin
- Department of Pathology, Murray State University, Breathitt Veterinary Center, Hopkinsville, KY 42240
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Smith DB, Sidman RD, Henke JS, Flanigin H, Labiner D, Evans CN. Scalp and depth recordings of induced deep cerebral potentials. Electroencephalogr Clin Neurophysiol 1983; 55:145-50. [PMID: 6185310 DOI: 10.1016/0013-4694(83)90180-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A balanced square wave was introduced between two adjacent depth electrodes implanted in the course of studying patients with intractable epilepsy and who were being considered for surgery. The stimulus current was designed so that charge density loading was well within limits of safety to avoid tissue damage. No neuronal activation was seen, and the stimulus intensity was significantly less than that used in subsequent stimulation session for the purpose of eliciting a clinical response and after-discharges. Averaging techniques were used to record the stimulus at distant electrodes both within the cerebrum and on the scalp. The recorded voltage decrement from the source was nearly identical with the theoretical voltage decrement predicted using principles of electric field theory in which the brain was assumed to be a homogeneous conductive medium. When the voltage recorded on the scalp was compared with the voltages recorded from depth electrodes, it was found that the effect of the highly resistive skull on voltage decrement was relatively less the more centric the source. This result also confirmed predictions based on electric field theory. Most significantly, voltages well within the physiologic range introduced in deep mesial temporal lobe structures were recorded from the scalp.
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