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Ducharme J, Auclair K. Use of bioconjugation with cytochrome P450 enzymes. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017. [PMID: 28625736 DOI: 10.1016/j.bbapap.2017.06.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Bioconjugation, defined as chemical modification of biomolecules, is widely employed in biological and biophysical studies. It can expand functional diversity and enable applications ranging from biocatalysis, biosensing and even therapy. This review summarizes how chemical modifications of cytochrome P450 enzymes (P450s or CYPs) have contributed to improving our understanding of these enzymes. Genetic modifications of P450s have also proven very useful but are not covered in this review. Bioconjugation has served to gain structural information and investigate the mechanism of P450s via photoaffinity labeling, mechanism-based inhibition (MBI) and fluorescence studies. P450 surface acetylation and protein cross-linking have contributed to the investigation of protein complexes formation involving P450 and its redox partner or other P450 enzymes. Finally, covalent immobilization on polymer surfaces or electrodes has benefited the areas of biocatalysis and biosensor design. This article is part of a Special Issue entitled: Cytochrome P450 biodiversity and biotechnology, edited by Erika Plettner, Gianfranco Gilardi, Luet Wong, Vlada Urlacher, Jared Goldstone.
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Affiliation(s)
- Julie Ducharme
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
| | - Karine Auclair
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada.
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2
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Substitutions at position 105 in SHV family β-lactamases decrease catalytic efficiency and cause inhibitor resistance. Antimicrob Agents Chemother 2012; 56:5678-86. [PMID: 22908166 DOI: 10.1128/aac.00711-12] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ambler position 105 in class A β-lactamases is implicated in resistance to clavulanic acid, although no clinical isolates with mutations at this site have been reported. We hypothesized that Y105 is important in resistance to clavulanic acid because changes in positioning of the inhibitor for ring oxygen protonation could occur. In addition, resistance to bicyclic 6-methylidene penems, which are interesting structural probes that inhibit all classes of serine β-lactamases with nanomolar affinity, might emerge with substitutions at position 105, especially with nonaromatic substitutions. All 19 variants of SHV-1 with variations at position 105 were prepared. Antimicrobial susceptibility testing showed that Escherichia coli DH10B expressing Y105 variants retained activity against ampicillin, except for the Y105L variant, which was susceptible to all β-lactams, similar to the case for the host control strain. Several variants had elevated MICs to ampicillin-clavulanate. However, all the variants remained susceptible to piperacillin in combination with a penem inhibitor (MIC, ≤2/4 mg/liter). The Y105E, -F, -M, and -R variants demonstrated reduced catalytic efficiency toward ampicillin compared to the wild-type (WT) enzyme, which was caused by increased K(m). Clavulanic acid and penem K(i) values were also increased for some of the variants, especially Y105E. Mutagenesis at position 105 in SHV yields mutants resistant to clavulanate with reduced catalytic efficiency for ampicillin and nitrocefin, similar to the case for the class A carbapenemase KPC-2. Our modeling analyses suggest that resistance is due to oxyanion hole distortion. Susceptibility to a penem inhibitor is retained although affinity is decreased, especially for the Y105E variant. Residue 105 is important to consider when designing new inhibitors.
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Wolf MC, Wang Y, Freiberg AN, Aguilar HC, Holbrook MR, Lee B. A catalytically and genetically optimized beta-lactamase-matrix based assay for sensitive, specific, and higher throughput analysis of native henipavirus entry characteristics. Virol J 2009; 6:119. [PMID: 19646266 PMCID: PMC2727953 DOI: 10.1186/1743-422x-6-119] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Accepted: 07/31/2009] [Indexed: 05/25/2023] Open
Abstract
Nipah virus (NiV) and Hendra virus (HeV) are the only paramyxoviruses requiring Biosafety Level 4 (BSL-4) containment. Thus, study of henipavirus entry at less than BSL-4 conditions necessitates the use of cell-cell fusion or pseudotyped reporter virus assays. Yet, these surrogate assays may not fully emulate the biological properties unique to the virus being studied. Thus, we developed a henipaviral entry assay based on a β-lactamase-Nipah Matrix (βla-M) fusion protein. We first codon-optimized the bacterial βla and the NiV-M genes to ensure efficient expression in mammalian cells. The βla-M construct was able to bud and form virus-like particles (VLPs) that morphologically resembled paramyxoviruses. βla-M efficiently incorporated both NiV and HeV fusion and attachment glycoproteins. Entry of these VLPs was detected by cytosolic delivery of βla-M, resulting in enzymatic and fluorescent conversion of the pre-loaded CCF2-AM substrate. Soluble henipavirus receptors (ephrinB2) or antibodies against the F and/or G proteins blocked VLP entry. Additionally, a Y105W mutation engineered into the catalytic site of βla increased the sensitivity of our βla-M based infection assays by 2-fold. In toto, these methods will provide a more biologically relevant assay for studying henipavirus entry at less than BSL-4 conditions.
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Affiliation(s)
- Mike C Wolf
- Department of Microbiology, Immunology, and Molecular Genetics, UCLA, Los Angeles, CA, USA 90095.
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4
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Kovač V, Radolović K, Habuš I, Siebler D, Heinze K, Rapić V. Conformational Analysis of β-Lactam-Containing Ferrocene Peptides. Eur J Inorg Chem 2009. [DOI: 10.1002/ejic.200800913] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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5
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Gellett AM, Huber PW, Higgins PJ. Synthesis of the unnatural amino acid N-N-(ferrocene-1-acetyl)-l-lysine: a novel organometallic nuclease. J Organomet Chem 2008; 693:2959-2962. [PMID: 19255618 PMCID: PMC2598734 DOI: 10.1016/j.jorganchem.2008.06.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
| | - Paul W. Huber
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
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Kim JH, Kim JW. Sequential solid-phase fabrication of bifunctional anchors on gold nanoparticles for controllable and scalable nanoscale structure assembly. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:5667-5671. [PMID: 18465887 DOI: 10.1021/la800506g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
This letter reports a serial solid-phase placement approach to synthesize anisotropically or symmetrically functionalized gold nanoparticles (AuNPs), in which the functionality and directionality (i.e., numbers, locations, and orientations) of the functional ligands are controlled. The solid-phase ligand exchange methodology using highly rigid filter papers enabled us to produce two types of bifunctionalized (bif-) AuNPs in a site-specific manner with increased yield and accuracy: (1) homobif-AuNPs with two carboxyl groups at approximately 180 degrees (para configuration) and (2) heterobif-AuNPs with one carboxyl and one amine functional groups at less than 180 degrees but greater than 90 degrees (meta configuration). Their chemical functionality was validated by 1H nuclear magnetic resonance as well as cyclic voltammetry after ferrocene ethylamine coupling reactions. The directional assemblies of 1D chains with homobif-AuNPs and 2D rings with heterobif-AuNPs were demonstrated through diamine and imidization coupling reactions, respectively, further validating their highly functional and directional selectivity, which is critical to realizing the practical nanoscale assembly.
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Affiliation(s)
- Jeong-Hwan Kim
- Department of Biological and Agricultural Engineering, University of Arkansas, Fayetteville, AR 72701, USA
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7
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Shumyantseva VV, Bulko TV, Archakov AI. Regulation of cytochrome P450 activity by physicochemical methods. RUSSIAN CHEMICAL REVIEWS 2007. [DOI: 10.1070/rc1999v068n10abeh000501] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Seiwert B, Karst U. Ferrocene-based derivatization in analytical chemistry. Anal Bioanal Chem 2007; 390:181-200. [PMID: 17934723 DOI: 10.1007/s00216-007-1639-7] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Revised: 09/14/2007] [Accepted: 09/17/2007] [Indexed: 11/25/2022]
Abstract
Ferrocene-based derivatization has raised considerable interest in many fields of analytical chemistry. This is due to the well-established chemistry of ferrocenes, which allows rapid and easy access to a large number of reagents and derivatives. Furthermore, the electrochemical properties of ferrocenes are attractive with respect to their detection. This paper summarizes the available reagents, the reaction conditions and the different approaches for detection. While electrochemical detection is still most widely used to detect ferrocene derivatives, e.g., in the field of DNA analysis, the emerging combination of analytical separation methods with electrochemistry, mass spectrometry and atomic spectroscopy allows ferrocenes to be applied more universally and in novel applications where strongly improved selectivity and limits of detection are required.
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Affiliation(s)
- Bettina Seiwert
- Institute of Inorganic and Analytical Chemistry, University of Münster, Corrensstr. 30, 48149, Münster, Germany
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Seiwert B, Karst U. Analysis of cysteine-containing proteins using precolumn derivatization with N-(2-ferroceneethyl)maleimide and liquid chromatography/electrochemistry/mass spectrometry. Anal Bioanal Chem 2007; 388:1633-42. [PMID: 17437089 DOI: 10.1007/s00216-007-1260-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Revised: 03/09/2007] [Accepted: 03/12/2007] [Indexed: 10/23/2022]
Abstract
N-(2-ferroceneethyl)maleimide (FEM) is introduced as an electroactive derivatizing agent for thiol functionalities in proteins. Using appropriate reaction conditions, the derivatization is completed within five minutes and no unspecific labeling of free amino functions is observed. Liquid chromatography/electrochemistry/mass spectrometry was used to detect the reaction products. The reagent is a useful tool for determining the number of free thiol groups or the total number of free and disulfide-bound thiol groups in proteins. The electrochemical cell provides additional information, because the increase in mass spectrometric response upon electrochemical oxidation of the neutral ferrocene to the charged ferrocinium groups is monitored. The method was successfully applied to the analysis of native proteins and their tryptic digests.
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Affiliation(s)
- Bettina Seiwert
- Chemical Analysis Group and MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500, AE Enschede, The Netherlands
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Haquette P, Salmain M, Svedlung K, Martel A, Rudolf B, Zakrzewski J, Cordier S, Roisnel T, Fosse C, Jaouen G. Cysteine-Specific, Covalent Anchoring of Transition Organometallic Complexes to the Protein Papain fromCarica papaya. Chembiochem 2007; 8:224-31. [PMID: 17167808 DOI: 10.1002/cbic.200600387] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Site-directed and covalent introduction of various transition metal-organic entities to the active site of the cysteine endoproteinase, papain, was achieved by treatment of this enzyme with a series of organometallic maleimide derivatives specially designed for the purpose. Kinetic studies made it clear that time-dependent irreversible inactivation of papain occurred in the presence of these organometallic maleimides as a result of Michael addition of the sulfhydryl of Cys25. The rate and mechanism of inactivation were highly dependent on the structure of the organometallic entity attached to the maleimide group. Combined ESI-MS and IR analysis indicated that all the resulting papain adducts contained one organometallic moiety per protein molecule. This confirmed that chemospecific introduction of the metal complexes was indeed achieved. Thus, three novel reagents for heavy-atom derivatization of protein crystals, which include ruthenium, rhenium and tungsten, are now available for the introduction of electron-dense scatterers for phasing of X-ray crystallographic data.
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Affiliation(s)
- Pierre Haquette
- Ecole Nationale Supérieure de Chimie de Paris, Laboratoire de Chimie et Biochimie des Complexes Moléculaires (UMR CNRS 7576), 75231 Paris Cedex 05, France
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Uchiyama S, Tomita R, Sekioka N, Imaizumi E, Hamana H, Hagiwara T. Application of polymaleimidostyrene as a convenient immobilization reagent of enzyme in biosensor. Bioelectrochemistry 2006; 68:119-25. [PMID: 16039167 DOI: 10.1016/j.bioelechem.2005.06.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2005] [Revised: 06/01/2005] [Accepted: 06/03/2005] [Indexed: 11/30/2022]
Abstract
Sulfhydryl groups of glucose oxidase (GOD) were reacted with maleimide groups of polymaleimidostyrene (PMS) which was coated onto the porous carbon sheet, and the carbon sheet immobilized by GOD was combined with an oxygen electrode to fabricate a glucose sensor. The activity of thiolated GOD immobilized to PMS is much larger than that of native GOD immobilized to PMS. The good linear relationship of glucose and oxygen current response was obtained in a concentration range from 0.1 to 2 mM and upper limit of linear range was found to be 3.0 mM. The immobilized GOD activity is highly dependent on pH at immobilization and the maximum activity was obtained at pH 5.5, probably because the SH groups of GOD that are indispensable for generation of enzyme activity is not exposed at this pH. It was found that PMS is very effective reagent to immobilize enzyme strongly via covalent bond, because high density of maleimide groups of PMS can catch not only exposed SH groups but also buried SH groups.
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Affiliation(s)
- Shunichi Uchiyama
- Department of Materials Science and Technology, Graduate School of Engineering, Saitama Institute of technology, 1690 Fusaiji, Okabe, Saitama 369-0293 Japan.
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Wang Y, Zhu X, Hu Z, Wang J, Zhou F. Voltammetric Determination of Surface-Confined Biomolecules withN-(2-Ethyl-ferrocene)maleimide. ELECTROANAL 2005. [DOI: 10.1002/elan.200503347] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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13
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Rudolf B, Palusiak M, Zakrzewski J, Salmain M, Jaouen G. Sulfhydryl-Selective, Covalent Labeling of Biomolecules with Transition Metallocarbonyl Complexes. Synthesis of (η5-C5H5)M(CO)3(η1-N-Maleimidato) (M = Mo, W), X-ray Structure, and Reactivity Studies. Bioconjug Chem 2005; 16:1218-24. [PMID: 16173801 DOI: 10.1021/bc050073d] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The photochemical reaction of (eta5-C5H5)Mo(CO)3I with maleimide in the presence of diisopropylamine yielded complex (eta5-C5H5)Mo(CO)3(eta1-N-maleimidato) 4 in 52% yield. The single-crystal X-ray structure of this complex was determined and shows unusual interactions between oxygen atoms of the maleimidato ligand and carbon atoms of the cis-CO ligands. The tungsten analogue of 4, (eta5-C5H5)W(CO)3(eta1-N-maleimidato) 5, was synthesized in 37% yield by the reaction of (eta5-C5H5)W(CO)3I with the thallium(I) salt of maleimide. Complexes 4 and 5 reacted with cysteine ethyl ester and glutathione to afford products of the addition of the sulfhydryl group to the ethylenic bond of the maleimidato ligand. The reaction of 4 and 5 with glutathione proceeded faster than the reaction of the analogous complex (eta5-C5H5)Fe(CO)2(eta1-N-maleimidato) (3). However, all these complexes react with glutathione more slowly than N-ethylmaleimide. Complexes 4 and 5 were used for labeling of bovine serum albumin (BSA), enriched in thiol groups by reaction with Traut's reagent. Reaction of thiolated BSA containing 7.4 SH groups with 4 and 5 gave bioconjugates bearing 6.9 and 6.4 metallocarbonyl moieties, respectively. Under the same conditions, reaction with 3 afforded a BSA conjugate containing 7.6 metallocarbonyl moieties. Labeling was presumed to be site-specific, as the number of metallocarbonyl entities matched very well with the initial number of SH groups measured for the thiolated BSA sample. IR spectra of BSA labeled with 4 and 5 show intense nu(C[triple bond]O)) bands (2042 and 1948 cm(-1) in the latter case), enabling sensitive detection of the bioconjugates in biological samples. Complexes 4 and 5 (especially the latter) should be of interest as heavy atom phasing reagents for protein X-ray crystallography.
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Affiliation(s)
- Bogna Rudolf
- Department of Organic Chemistry, University of Lodz, 90-136 Lodz, Narutowicza 68, Poland
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Poljak T, Molčanov K, Višnjevac A, Habuš I, Kovač V, Rapić V. Synthesis and structure of trans-(+)-(3S,4S)-3-amino-4-ferrocenyl-1-p-methoxyphenylazetidin-2-one. J Mol Struct 2005. [DOI: 10.1016/j.molstruc.2005.04.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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15
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Pariagh S, Tasker KM, Fry FH, Holme AL, Collins CA, Okarter N, Gutowski N, Jacob C. Asymmetric organotellurides as potent antioxidants and building blocks of protein conjugates. Org Biomol Chem 2005; 3:975-80. [PMID: 15750638 DOI: 10.1039/b500409h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
New asymmetric organotellurides exhibiting good antioxidant properties in vitro and in cell culture can be attached to human serum albumin.
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Affiliation(s)
- Sandra Pariagh
- Biocatalysis Centre, School of Biological and Chemical Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
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Wang Y, Yao X, Wang J, Zhou F. Attachment of Amine- and Maleimide-Containing Ferrocene Derivatives onto Self-Assembled Alkanethiol and Alkanedithiol Monolayers: Voltammetric Evaluation of Cross-Linking Efficiencies and Surface Coverage of Electroactive Groups. ELECTROANAL 2004. [DOI: 10.1002/elan.200403057] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Doucet N, De Wals PY, Pelletier JN. Site-saturation mutagenesis of Tyr-105 reveals its importance in substrate stabilization and discrimination in TEM-1 beta-lactamase. J Biol Chem 2004; 279:46295-303. [PMID: 15326193 DOI: 10.1074/jbc.m407606200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The conserved Class A beta-lactamase active site residue Tyr-105 was substituted by saturation mutagenesis in TEM-1 beta-lactamase from Escherichia coli in order to clarify its role in enzyme activity and in substrate stabilization and discrimination. Minimum inhibitory concentrations were calculated for E. coli cells harboring each Y105X mutant in the presence of various penicillin and cephalosporin antibiotics. We found that only aromatic residues as well as asparagine replacements conferred high in vivo survival rates for all substrates tested. At position 105, the small residues alanine and glycine provide weak substrate discrimination as evidenced by the difference in benzylpenicillin hydrolysis relative to cephalothin, two typical penicillin and cephalosporin antibiotics. Kinetic analyses of mutants of interest revealed that the Y105X replacements have a greater effect on K(m) than k(cat), highlighting the importance of Tyr-105 in substrate recognition. Finally, by performing a short molecular dynamics study on a restricted set of Y105X mutants of TEM-1, we found that the strong aromatic bias observed at position 105 in Class A beta-lactamases is primarily defined by a structural requirement, selecting planar residues that form a stabilizing wall to the active site. The adopted conformation of residue 105 prevents detrimental steric interactions with the substrate molecule in the active site cavity and provides a rationalization for the strong aromatic bias found in nature at this position among Class A beta-lactamases.
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Affiliation(s)
- Nicolas Doucet
- Département de Biochimie and Département de chimie, Université de Montréal, C. P. 6128, Succursale Centre-ville, Montréal, Québec H3C 3J7, Canada
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Salmain M, Jaouen G. Side-chain selective and covalent labelling of proteins with transition organometallic complexes. Perspectives in biology. CR CHIM 2003. [DOI: 10.1016/s1631-0748(03)00023-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Lo KKW, Hui WK, Ng DCM, Cheung KK. Synthesis, characterization, photophysical properties, and biological labeling studies of a series of luminescent rhenium(I) polypyridine maleimide complexes. Inorg Chem 2002; 41:40-6. [PMID: 11782142 DOI: 10.1021/ic010602z] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report the synthesis, characterization, and photophysical properties of a series of rhenium(I) polypyridine maleimide complexes [Re(N-N)(CO)(3)(py-3-mal)](CF(3)SO(3)) [N-N = 1,10-phenanthroline, phen (1), 2,9-dimethyl-1,10-phenanthroline, 2,9-Me(2)-phen (2), 3,4,7,8-tetramethyl-1,10-phenanthroline, 3,4,7,8-Me(4)-phen (3), 4,7-diphenyl-1,10-phenanthroline, 4,7-Ph(2)-phen (4), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, 2,9-Me(2)-4,7-Ph(2)-phen (5), 2,2'-biquinonine, biq (6); py-3-mal = N-(3-pyridyl)maleimide]. The X-ray crystal structure of complex 2 has been investigated. Upon excitation, the complexes exhibit intense and long-lived photoluminescence in fluid solutions at 298 K. The emission wavelengths range from 514 to 654 nm, and the emission lifetimes fall in the microsecond time scale. The luminescence is assigned to originate from a metal-to-ligand charge-transfer MLCT [dpi(Re) --> pi*(diimine)] triplet excited state. As the maleimide group can react with the sulfhydryl group to form a stable thioether moiety, these complexes have been used as thiol-specific luminescent labels for a thiolated oligonucleotide, glutathione, and bovine serum albumin and human serum albumin. The photoluminescence properties of the labeled biological species have also been investigated.
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Affiliation(s)
- Kenneth Kam-Wing Lo
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, PR China.
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Sierra MA, Mancheño MJ, Vicente R, Gómez-Gallego M. Synthesis of ferrocene-substituted 2-azetidinones. J Org Chem 2001; 66:8920-5. [PMID: 11749623 DOI: 10.1021/jo015961q] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The photochemical reaction of alkoxychromium(0)carbene complexes and ferrocene mono- and disubstituted imines formed 2-azetidinones having one or two ferrocene moieties in good yields. Yields decrease when the carbene moiety bears an aminoferrocene moiety attached to the carbene carbon, while complex 9 having the ferrocene directly bonded to the carbene carbon was totally inert in these reactions. Access to beta-lactams with the ferrocene tethered to the C3 position through a methylene group was gained using the lithium enolate derived from ethyl 3-ferrocenylpropanoate. The reaction of this enolate produced two unexpected processes. Thus, 2-azetidinone 15 having an hydroxyl group at the C3 position was obtained together with the expected beta-lactam 14, by reaction of the lithium enolate of ethyl 3-ferrocenylpropenoate and imine 1. Additionally, unsaturated amide 17 was obtained by base-promoted Hoffmann-like breakage of the beta-lactam ring formed in the reaction of the same enolate and imine 2. Oxidation of the anion at the C3 of the 2-azetidinone ring on compound 14, as well as the sterically driven ring-breakage of the C3 anion derived from the nonisolated 2-azetidinone 18, should be responsible for this behavior.
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Affiliation(s)
- M A Sierra
- Departamento de Química Orgánica, Facultad de Química, Universidad Complutense, 28040-Madrid, Spain.
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