scholarly journals Resolving Phenylalanine Metabolism Sheds Light on Natural Synthesis of Penicillin G in Penicillium chrysogenum

2011 ◽  
Vol 11 (2) ◽  
pp. 238-249 ◽  
Author(s):  
Tânia Veiga ◽  
Daniel Solis-Escalante ◽  
Gabriele Romagnoli ◽  
Angela ten Pierick ◽  
Mark Hanemaaijer ◽  
...  

ABSTRACTThe industrial production of penicillin G byPenicillium chrysogenumrequires the supplementation of the growth medium with the side chain precursor phenylacetate. The growth ofP. chrysogenumwith phenylalanine as the sole nitrogen source resulted in the extracellular production of phenylacetate and penicillin G. To analyze this natural pathway for penicillin G production, chemostat cultures were switched to [U-13C]phenylalanine as the nitrogen source. The quantification and modeling of the dynamics of labeled metabolites indicated that phenylalanine was (i) incorporated in nascent protein, (ii) transaminated to phenylpyruvate and further converted by oxidation or by decarboxylation, and (iii) hydroxylated to tyrosine and subsequently metabolized via the homogentisate pathway. The involvement of the homogentisate pathway was supported by the comparative transcriptome analysis ofP. chrysogenumcultures grown with phenylalanine and with (NH4)2SO4as the nitrogen source. This transcriptome analysis also enabled the identification of two putative 2-oxo acid decarboxylase genes (Pc13g9300 and Pc18g01490). cDNAs of both genes were cloned and expressed in the 2-oxo-acid-decarboxylase-freeSaccharomyces cerevisiaestrain CEN.PK711-7C (pdc1 pdc5 pdc6Δ aro10Δ thi3Δ). The introduction of Pc13g09300 restored the growth of thisS. cerevisiaemutant on glucose and phenylalanine, thereby demonstrating that Pc13g09300 encodes a dual-substrate pyruvate and phenylpyruvate decarboxylase, which plays a key role in an Ehrlich-type pathway for the production of phenylacetate inP. chrysogenum. These results provide a basis for the metabolic engineering ofP. chrysogenumfor the production of the penicillin G side chain precursor phenylacetate.

2005 ◽  
Vol 71 (6) ◽  
pp. 3276-3284 ◽  
Author(s):  
Zeynep Vuralhan ◽  
Marijke A. H. Luttik ◽  
Siew Leng Tai ◽  
Viktor M. Boer ◽  
Marcos A. Morais ◽  
...  

ABSTRACT Aerobic, glucose-limited chemostat cultures of Saccharomyces cerevisiae CEN.PK113-7D were grown with different nitrogen sources. Cultures grown with phenylalanine, leucine, or methionine as a nitrogen source contained high levels of the corresponding fusel alcohols and organic acids, indicating activity of the Ehrlich pathway. Also, fusel alcohols derived from the other two amino acids were detected in the supernatant, suggesting the involvement of a common enzyme activity. Transcript level analysis revealed that among the five thiamine-pyrophospate-dependent decarboxylases (PDC1, PDC5, PDC6, ARO10, and THI3), only ARO10 was transcriptionally up-regulated when phenylalanine, leucine, or methionine was used as a nitrogen source compared to growth on ammonia, proline, and asparagine. Moreover, 2-oxo acid decarboxylase activity measured in cell extract from CEN.PK113-7D grown with phenylalanine, methionine, or leucine displayed similar broad-substrate 2-oxo acid decarboxylase activity. Constitutive expression of ARO10 in ethanol-limited chemostat cultures in a strain lacking the five thiamine-pyrophosphate-dependent decarboxylases, grown with ammonia as a nitrogen source, led to a measurable decarboxylase activity with phenylalanine-, leucine-, and methionine-derived 2-oxo acids. Moreover, even with ammonia as the nitrogen source, these cultures produced significant amounts of the corresponding fusel alcohols. Nonetheless, the constitutive expression of ARO10 in an isogenic wild-type strain grown in a glucose-limited chemostat with ammonia did not lead to any 2-oxo acid decarboxylase activity. Furthermore, even when ARO10 was constitutively expressed, growth with phenylalanine as the nitrogen source led to increased decarboxylase activities in cell extracts. The results reported here indicate the involvement of posttranscriptional regulation and/or a second protein in the ARO10-dependent, broad-substrate-specificity decarboxylase activity.


2007 ◽  
Vol 9 (1) ◽  
pp. 112-123 ◽  
Author(s):  
Roelco J. Kleijn ◽  
Feng Liu ◽  
Wouter A. van Winden ◽  
Walter M. van Gulik ◽  
Cor Ras ◽  
...  

2012 ◽  
Vol 16 (6) ◽  
pp. 320-333 ◽  
Author(s):  
Tânia Veiga ◽  
Jeroen G. Nijland ◽  
Arnold J.M. Driessen ◽  
Roel A.L. Bovenberg ◽  
Hesselein Touw ◽  
...  

1980 ◽  
Vol 1 (7) ◽  
pp. 197-201
Author(s):  
Michael J. Kraemer ◽  
Arnold L. Smith

Ampicillin, first introduced in 1961, has probably become the most widely used penicillin in clinical pediatrics. STRUCTURE ACTIVITY RELATIONSHIPS All penicillins contain the 6-amino penicillanic acid moiety (Fig 1). Its structure includes a thiazolidine ring (A), a β-lactam ring (B), the source of antibacterial activity, and an acyl side chain (R), containing a variety of substitutions creating the family of semisynthetic penicillins. The only difference between ampicillin and penicillin G is the presence of an amino group in the acyl side chain (Fig 1). PHARMACOLOGY AND BACTERIOLOGY Ampicillin is a semisynthetic penicillin, active against Streptococus pneumoniae and certain Gram-negative bacteria, including most Haemophilus influenzae, Escherichia coli, and certain Proteus species. Compared to penicillin G, it has increased stability in acid solutions: a property facilitating oral administration and absorption. It penetrates into most body tissues; effective entry into CSF, however, occurs only with inflamed meninges. The serum half-life with normal renal function varies from four hours in newborns1 to 1.3 hours in adults.2 Ampicillin can cause an allergic, or nonallergic skin rash (Fig 2). ALLERGY Allergy (for the purposes of this discussion) is defined as a specific immunologic interaction, between either antigen and antibody, or antigen with a sensitized lymphocyte, resulting in a clinically deleterious effect. Implicit is a prior contact with the antigen.


1988 ◽  
Vol 66 (11) ◽  
pp. 2733-2750 ◽  
Author(s):  
Saul Wolfe ◽  
Kiyull Yang ◽  
Maged Khalil

Using the MMPEN parameters of Allinger's MMP2(85) force field, a conformational analysis has been performed on four biologically active penicillins; D-ampicillin, L-α-phenoxyethylpenicillin, penicillin G, and penicillin V, and on five biologically inactive or much less active penicillins: L-ampicillin, D-α-phenoxyethylpenicillin, N-methylpenicillin G, 6α-methylpenicillin G, and bisnorpenicillin G. Antibacterial activity is found to be associated with the existence of a global minimum having a compact structure, whose convex face is accessible to a penicillin binding protein (PBP), with the C3-carboxyl group and the side-chain N-H exposed on this face. Using the MMPEP parameters of MMP2(85), a conformational analysis has been performed on phenylacetyl-D-Ala-D-Ala-O−, a peptide model of the normal substrate of a PBP. Labischinski's global minimum has been reproduced, along with structures that correspond to Tipper and Strominger's proposal that the N4—C7 bond of a penicillin corresponds to the Ala–Ala peptide bond, and to Hasan's proposal that the N4—C5 bond of penicillin corresponds to the peptide bond. For both models, conformations of the peptide related to the pseudoaxial and pseudoequatorial conformations of the thiazolidine ring of penicillin G have been examined. It is concluded that penicillin is not a structural analog of the global minimum of the peptide; however, comparisons based on unbound conformations of PBP substrates are unable to determine which model is more appropriate, or which conformation of penicillin G is the biologically significant one. Using the ECEPP/MMPEP strategy, a model of the active site of a PBP has been obtained, following a search of 200,000 structures of the peptide Ac-NH-Val-Gly-Ser-Val-Thr-Lys-NH-Me. This peptide contains the sequence at the active site of a PBP of Streptomyces R61, for which it is also known that the C3-carboxyl group of penicillin binds to the ε-amino group of lysine, and the β-lactam reacts chemically with the serine OH. The lysine and serine side chains and the C-terminal carbonyl group are found to occupy the concave face of the active site model.A strategy for the docking of penicillins or peptides to this model, with full minimization of the conformational energies of the complexes, has been devised. All active penicillins bind through strong hydrogen bonds to the C3-carboxyl group and the side-chain N-H, and with a four-centered relationship between the O-H of serine and the (O)C-N of the β-lactam ring. The geometrical parameters of this relationship are reminiscent of those found in the gas phase transition state of neutral hydration of a carbonyl group. When the energies of formation and geometries of the pseudoaxial and pseudoequatorial penicillin G complexes are examined, there is now a clear preference for the binding of the pseudoaxial conformation, which is the global minimum of the uncomplexed penicillin in this case. A similar examination of the peptide complexes reveals that only the conformation of the peptide that corresponds to Tipper and Strominger's model, and is based on the pseudoaxial conformation of penicillin G, can form a complex with a geometry and energy comparable to those of a biologically active penicillin.


2015 ◽  
Vol 197 (17) ◽  
pp. 2831-2839 ◽  
Author(s):  
Katherine A. Miller ◽  
Robert S. Phillips ◽  
Paul B. Kilgore ◽  
Grady L. Smith ◽  
Timothy R. Hoover

ABSTRACTSalmonella entericserovar Typhimurium, a major cause of food-borne illness, is capable of using a variety of carbon and nitrogen sources. Fructoselysine and glucoselysine are Maillard reaction products formed by the reaction of glucose or fructose, respectively, with the ε-amine group of lysine. We report here thatS. Typhimurium utilizes fructoselysine and glucoselysine as carbon and nitrogen sources via a mannose family phosphotransferase (PTS) encoded bygfrABCD(glucoselysine/fructoselysine PTS components EIIA, EIIB, EIIC, and EIID; locus numbers STM14_5449 to STM14_5454 inS. Typhimurium 14028s). Genes coding for two predicted deglycases within thegfroperon,gfrEandgfrF, were required for growth with glucoselysine and fructoselysine, respectively. GfrF demonstrated fructoselysine-6-phosphate deglycase activity in a coupled enzyme assay. The biochemical and genetic analyses were consistent with a pathway in which fructoselysine and glucoselysine are phosphorylated at the C-6 position of the sugar by the GfrABCD PTS as they are transported across the membrane. The resulting fructoselysine-6-phosphate and glucoselysine-6-phosphate subsequently are cleaved by GfrF and GfrE to form lysine and glucose-6-phosphate or fructose-6-phosphate. Interestingly, althoughS. Typhimurium can use lysine derived from fructoselysine or glucoselysine as a sole nitrogen source, it cannot use exogenous lysine as a nitrogen source to support growth. Expression ofgfrABCDEFwas dependent on the alternative sigma factor RpoN (σ54) and an RpoN-dependent LevR-like activator, which we designated GfrR.IMPORTANCESalmonellaphysiology has been studied intensively, but there is much we do not know regarding the repertoire of nutrients these bacteria are able to use for growth. This study shows that a previously uncharacterized PTS and associated enzymes function together to transport and catabolize fructoselysine and glucoselysine. Knowledge of the range of nutrients thatSalmonellautilizes is important, as it could lead to the development of new strategies for reducing the load ofSalmonellain food animals, thereby mitigating its entry into the human food supply.


2021 ◽  
Vol 7 (7) ◽  
Author(s):  
Prashant P. Patil ◽  
Sanjeet Kumar ◽  
Amandeep Kaur ◽  
Samriti Midha ◽  
Kanika Bansal ◽  
...  

Stenotrophomonas maltophilia is a typical example of an environmental originated opportunistic human pathogen, which can thrive at different habitats including the human body and can cause a wide range of infections. It must cope with heat stress during transition from the environment to the human body as the physiological temperature of the human body (37 °C) is higher than environmental niches (22–30 °C). Interestingly, S. rhizophila a phylogenetic neighbour of S. maltophilia within genus Stenotrophomonas is unable to grow at 37 °C. Thus, it is crucial to understand how S. maltophilia is adapted to human body temperature, which could suggest its evolution as an opportunistic human pathogen. In this study, we have performed comparative transcriptome analysis of S. maltophilia grown at 28 and 37 °C as temperature representative for environmental niches and the human body, respectively. RNA-Seq analysis revealed several interesting findings showing alterations in gene-expression levels at 28 and 37 °C, which can play an important role during infection. We have observed downregulation of genes involved in cellular motility, energy production and metabolism, replication and repair whereas upregulation of VirB/D4 type IV secretion system, aerotaxis, cation diffusion facilitator family transporter and LacI family transcriptional regulators at 37 °C. Microscopy and plate assays corroborated altered expression of genes involved in motility. The results obtained enhance our understanding of the strategies employed by S. maltophilia during adaptation towards the human body.


2014 ◽  
Vol 58 (9) ◽  
pp. 5191-5201 ◽  
Author(s):  
Giorgia Letizia Marcone ◽  
Elisa Binda ◽  
Lucia Carrano ◽  
Mervyn Bibb ◽  
Flavia Marinelli

ABSTRACTGlycopeptides and β-lactams inhibit bacterial peptidoglycan synthesis in Gram-positive bacteria; resistance to these antibiotics is studied intensively in enterococci and staphylococci because of their relevance to infectious disease. Much less is known about antibiotic resistance in glycopeptide-producing actinomycetes that are likely to represent the evolutionary source of resistance determinants found in bacterial pathogens.Nonomuraeasp. ATCC 39727, the producer of A40926 (the precursor for the semisynthetic dalbavancin), does not harbor the canonicalvanHAXgenes. Consequently, we investigated the role of the β-lactam-sensitived,d-peptidase/d,d-carboxypeptidase encoded byvanYn, the onlyvan-like gene found in the A40926 biosynthetic gene cluster, in conferring immunity to the antibiotic inNonomuraeasp. ATCC 39727. Taking advantage of the tools developed recently to genetically manipulate this uncommon actinomycete, we variedvanYngene dosage and expressedvanHatAatXatfrom the teicoplanin producerActinoplanes teichomyceticusinNonomuraeasp. ATCC 39727. Knocking outvanYn, complementing avanYnmutant, or duplicatingvanYnhad no effect on growth but influenced antibiotic resistance and, in the cases of complementation and duplication, antibiotic production.Nonomuraeasp. ATCC 39727 was found to be resistant to penicillins, but its glycopeptide resistance was diminished in the presence of penicillin G, which inhibits VanYnactivity. The heterologous expression ofvanHatAatXatincreased A40926 resistance inNonomuraeasp. ATCC 39727 but did not increase antibiotic production, indicating that the level of antibiotic production is not directly determined by the level of resistance. ThevanYn-based self-resistance inNonomuraeasp. ATCC 39727 resembles the glycopeptide resistance mechanism described recently in mutants ofEnterococcus faeciumselectedin vitrofor high-level resistance to glycopeptides and penicillins.


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