The natural occurring Y129F polymorphism in Rhizopus oryzae (R. arrhizus) Cyp51Ap accounts for its intrinsic voriconazole resistance

2021 ◽  
Author(s):  
Daiana Macedo ◽  
Florencia Leonardelli ◽  
Matias S Cabeza ◽  
Soledad Gamarra ◽  
Guillermo Garcia-Effron
Keyword(s):  
Experimental Data ◽  
Amino Acid ◽  
Rhizopus Oryzae ◽  
The Other ◽  
Amino Acid Residues ◽  
Wild Type ◽  
Fluconazole Resistance ◽  
Resistance Phenotype ◽  
Naturally Occurring

Abstract Rhizopus oryzae (heterotypic synonym: R. arrhizus) intrinsic voriconazole and fluconazole resistance has been linked to its CYP51A gene. However, the amino acid residues involved in this phenotype have not yet been established. A comparison between R. oryzae and Aspergillus fumigatus Cyp51Ap sequences showed differences in several amino acid residues. Some of them were already linked with voriconazole resistance in A. fumigatus. The objective of this work was to analyze the role of two natural polymorphisms in the intrinsic voriconazole resistance phenotype of R. oryzae (Y129F and T290A, equivalent to Y121F and T289A seen in triazole-resistant A. fumigatus). We have generated A. fumigatus chimeric strains harboring different R. oryzae CYP51A genes (wild-type and mutants). These mutant R. oryzae CYP51A genes were designed to carry nucleotide changes that produce mutations at Cyp51Ap residues 129 and 290 (emulating the Cyp51Ap protein of azole susceptible A. fumigatus). Antifungal susceptibilities were evaluated for all the obtained mutants. The polymorphism T290A (alone or in combination with Y129F) had no impact on triazole MIC. On the other hand, a > 8-fold decrease in voriconazole MICs was observed in A. fumigatus chimeric strains harboring the RoCYP51Ap-F129Y. This phenotype supports the assumption that the naturally occurring polymorphism Y129F at R. oryzae Cyp51Ap is responsible for its voriconazole resistance phenotype. In addition, these chimeric mutants were posaconazole hypersusceptible. Thus, our experimental data demonstrate that the RoCYP51Ap-F129 residue strongly impacts VRC susceptibility and that it would be related with posaconazole-RoCYP51Ap interaction. Lay summary Rhizopus oryzae is intrinsically resistant to voriconazole, a commonly used antifungal agent. In this work, we analyze the role of two natural polymorphisms present in the target of azole drugs. We established that F129 residue is responsible of the intrinsic voriconazole resistance in this species.

Modulation of procaspase-7 self-activation by PEST amino acid residues of the N-terminal prodomain and intersubunit linker

2017 ◽  
Vol 95 (6) ◽  
pp. 634-643
Author(s):  
Juliano Alves ◽  
Miguel Garay-Malpartida ◽  
João M. Occhiucci ◽  
José E. Belizário
Keyword(s):  
Amino Acid ◽  
Large Subunit ◽  
Small Subunit ◽  
Cleavage Sites ◽  
Amino Acid Residues ◽  
Wild Type ◽  
Caspase 7 ◽  
Caspase Family ◽  
The Impact

Procaspase-7 zymogen polypeptide is composed of a short prodomain, a large subunit (p20), and a small subunit (p10) connected to an intersubunit linker. Caspase-7 is activated by an initiator caspase-8 and -9, or by autocatalysis after specific cleavage at IQAD198↓S located at the intersubunit linker. Previously, we identified that PEST regions made of amino acid residues Pro (P), Glu (E), Asp (D), Ser (S), Thr (T), Asn (N), and Gln (Q) are conserved flanking amino acid residues in the cleavage sites within a prodomain and intersubunit linker of all caspase family members. Here we tested the impact of alanine substitution of PEST amino acid residues on procaspase-7 proteolytic self-activation directly in Escherichia coli. The p20 and p10 subunit cleavage were significantly delayed in double caspase-7 mutants in the prodomain (N18A/P26A) and intersubunit linker (S199A/P201A), compared with the wild-type caspase-7. The S199A/P201A mutants effectively inhibited the p10 small subunit cleavage. However, the mutations did not change the kinetic parameters (kcat/KM) and optimal tetrapeptide specificity (DEVD) of the purified mutant enzymes. The results suggest a role of PEST-amino acid residues in the molecular mechanism for prodomain and intersubunit cleavage and caspase-7 self-activation.

scholarly journals Relief of autoinhibition of the electrogenic Na-HCO3 cotransporter NBCe1-B: role of IRBIT vs. amino-terminal truncation

2012 ◽  
Vol 302 (3) ◽  
pp. C518-C526 ◽  
Author(s):  
Seong-Ki Lee ◽  
Walter F. Boron ◽  
Mark D. Parker
Keyword(s):  
Amino Acid ◽  
Relative Magnitude ◽  
Amino Acid Residues ◽  
Wild Type ◽  
Amino Terminal ◽  
Sodium Bicarbonate Cotransporter ◽  
Electrode Voltage ◽  
Binding Determinants ◽  
The Relationship

Two maneuvers known to stimulate electrogenic sodium bicarbonate cotransporter 1 (NBCe1) activity are 1) deletion from the cytosolic amino-terminus (Nt) of NBCe1-C of an 87-amino acid sequence that contains an autoinhibitory domain (AID); and 2) binding of the protein IRBIT to elements within the same 87-amino acid module in a different variant, NBCe1-B. Helpful to understanding the relationship between these two phenomena would be an appreciation of the relative magnitude of stimulation caused by each maneuver for the same NBCe1 variant. In the present study, we performed two-electrode voltage-clamp on Xenopus oocytes expressing human NBCe1-B constructs, with and without human IRBIT constructs. We find that removal of the AID stimulates NBCe1-B to the same extent as coexpression of wild-type IRBIT. The potency of wild-type IRBIT apparently is reduced by the action of endogenous oocyte protein phosphatases: a mutant IRBIT that cannot be influenced by the action of protein phosphatase-1 stimulates NBCe1-B to an extent 50% greater than can be achieved by removal of the NBCe1-B AID. Thus the stimulatory effect of IRBIT cannot be explained solely by masking of autoinhibitory determinants within the AID. Finally, we find that an NBCe1-B construct that lacks amino acid residues 2–16 of the Nt is fully autoinhibited, but cannot be stimulated by IRBIT, indicating that autoinhibitory and IRBIT-binding determinants within the cytosolic Nt are not identical.

scholarly journals Identification of amino acid residues responsible for differences in substrate specificity and inhibitor sensitivity between two human liver dihydrodiol dehydrogenase isoenzymes by site-directed mutagenesis

1997 ◽  
Vol 323 (1) ◽  
pp. 61-64 ◽  
Author(s):  
Kazuya MATSUURA ◽  
Yoshihiro DEYASHIKI ◽  
Kumiko SATO ◽  
Naoko ISHIDA ◽  
Gunpei MIWA ◽  
...  
Keyword(s):  
Amino Acid ◽  
Human Liver ◽  
Hydroxysteroid Dehydrogenase ◽  
The Other ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Amino Acid Residues ◽  
Dihydrodiol Dehydrogenase ◽  
Inactive Protein

Human liver dihydrodiol dehydrogenase isoenzymes (DD1 and DD2), in which only seven amino acid residues are substituted, differ remarkably in specificity for steroidal substrates and inhibitor sensitivity: DD1 shows 20α-hydroxysteroid dehydrogenase activity and sensitivity to 1,10-phenanthroline, whereas DD2 oxidizes 3α-hydroxysteroids and is highly inhibited by bile acids. In the present study we performed site-directed mutagenesis of the seven residues (Thr-38, Arg-47, Leu-54, Cys-87, Val-151, Arg-170 and Gln-172) of DD1 to the corresponding residues (Val, His, Val, Ser, Met, His and Leu respectively) of DD2. Of the seven mutations, only the replacement of Leu-54 with Val produced an enzyme that had almost the same properties as DD2. No significant changes were observed in the other mutant enzymes. An additional site-directed mutagenesis of Tyr-55 of DD1 to Phe yielded an inactive protein, suggesting the catalytically important role of this residue. Thus a residue at a position before the catalytic Tyr residue might play a key role in determining the orientation of the substrates and inhibitors.

Oxytocin analogues with non-coded amino acid residues in position 8: [8-Neopentylglycine]oxytocin and [8-cycloleucine]oxytocin

1987 ◽  
Vol 52 (9) ◽  
pp. 2317-2325 ◽  
Author(s):  
Jan Hlaváček ◽  
Jan Pospíšek ◽  
Jiřina Slaninová ◽  
Walter Y. Chan ◽  
Victor J. Hruby
Keyword(s):  
Amino Acid ◽  
Solid Phase Synthesis ◽  
Solid Phase ◽  
The Other ◽  
Amino Acid Residues ◽  
Phase Synthesis ◽  
Other Hand ◽  
Fragment Condensation

[8-Neopentylglycine]oxytocin (II) and [8-cycloleucine]oxytocin (III) were prepared by a combination of solid-phase synthesis and fragment condensation. Both analogues exhibited decreased uterotonic potency in vitro, each being about 15-30% that of oxytocin. Analogue II also displayed similarly decreased uterotonic potency in vivo and galactogogic potency. On the other hand, analogue III exhibited almost the same potency as oxytocin in the uterotonic assay in vivo and in the galactogogic assay.

An ESR study of the peroxidase reaction catalyzed by human methaemoglobin and methaemoglobin-haptoglobin complex

1991 ◽  
Vol 56 (4) ◽  
pp. 923-932
Author(s):  
Jana Stejskalová ◽  
Pavel Stopka ◽  
Zdeněk Pavlíček
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Amino Acid ◽  
Peroxidase Activity ◽  
Amino Acid Analysis ◽  
Superoxide Radical ◽  
Esr Spectra ◽  
The Other ◽  
Delocalized Electron

The ESR spectra of peroxidase systems of methaemoglobin-ascorbic acid-hydrogen peroxide and methaemoglobin-haptoglobin complex-ascorbic acid-hydrogen peroxide have been measured in the acetate buffer of pH 4.5. For the system with methaemoglobin an asymmetrical signal with g ~ 2 has been observed which is interpreted as the perpendicular region of anisotropic spectrum of superoxide radical. On the other hand, for the system with methaemoglobin-haptoglobin complex the observed signal with g ~ 2 is symmetrical and is interpreted as a signal of delocalized electron. After realization of three repeatedly induced peroxidase processes the ESR signal of the perpendicular part of anisotropic spectrum of superoxide radical is distinctly diminished, whereas the signal of delocalized electron remains practically unchanged. An amino acid analysis of methaemoglobin along with results of the ESR measurements make it possible to derive a hypothesis about the role of haptoglobin in increasing of the peroxidase activity of methaemoglobin.

scholarly journals The Role of Arg13 in Protein Phosphatase M tPphA from Thermosynechococcus elongatus

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Jiyong Su ◽  
Karl Forchhammer
Keyword(s):  
Amino Acid ◽  
Protein Phosphatase ◽  
Arginine Residue ◽  
Side Chain ◽  
Wild Type ◽  
Catalytic Center ◽  
Nitrophenyl Phosphate ◽  
Reduced Activity ◽  
Amino Acid Variants

A highly conserved arginine residue is close to the catalytic center of PPM/PP2C-type protein phosphatases. Different crystal structures of PPM/PP2C homologues revealed that the guanidinium side chain of this arginine residue can adopt variable conformations and may bind ligands, suggesting an important role of this residue during catalysis. In this paper, we randomly mutated Arginine 13 of tPphA, a PPM/PP2C-type phosphatase from Thermosynechococcus elongatus, and obtained 18 different amino acid variants. The generated variants were tested towards p-nitrophenyl phosphate and various phosphopeptides. Towards p-nitrophenyl phosphate as substrate, twelve variants showed 3–7 times higher Km values than wild-type tPphA and four variants (R13D, R13F, R13L, and R13W) completely lost activity. Strikingly, these variants were still able to dephosphorylate phosphopeptides, although with strongly reduced activity. The specific inability of some Arg-13 variants to hydrolyze p-nitrophenyl phosphate highlights the importance of additional substrate interactions apart from the substrate phosphate for catalysis. The properties of the R13 variants indicate that this residue assists in substrate binding.

scholarly journals Deletion of the Actin-Associated Tropomyosin Tpm3 Leads to Reduced Cell Complexity in Cultured Hippocampal Neurons—New Insights into the Role of the C-Terminal Region of Tpm3.1

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 715
Author(s):  
Tamara Tomanić ◽  
Claire Martin ◽  
Holly Stefen ◽  
Esmeralda Parić ◽  
Peter Gunning ◽  
...  
Keyword(s):  
Amino Acid ◽  
Hippocampal Neurons ◽  
Molecular Mechanisms ◽  
Growth Cones ◽  
Amino Acid Residues ◽  
Terminal Amino Acid ◽  
C Terminus ◽  
Primary Mouse ◽  
Terminal Amino

Tropomyosins (Tpms) have been described as master regulators of actin, with Tpm3 products shown to be involved in early developmental processes, and the Tpm3 isoform Tpm3.1 controlling changes in the size of neuronal growth cones and neurite growth. Here, we used primary mouse hippocampal neurons of C57/Bl6 wild type and Bl6Tpm3flox transgenic mice to carry out morphometric analyses in response to the absence of Tpm3 products, as well as to investigate the effect of C-terminal truncation on the ability of Tpm3.1 to modulate neuronal morphogenesis. We found that the knock-out of Tpm3 leads to decreased neurite length and complexity, and that the deletion of two amino acid residues at the C-terminus of Tpm3.1 leads to more detrimental changes in neurite morphology than the deletion of six amino acid residues. We also found that Tpm3.1 that lacks the 6 C-terminal amino acid residues does not associate with stress fibres, does not segregate to the tips of neurites, and does not impact the amount of the filamentous actin pool at the axonal growth cones, as opposed to Tpm3.1, which lacks the two C-terminal amino acid residues. Our study provides further insight into the role of both Tpm3 products and the C-terminus of Tpm3.1, and it forms the basis for future studies that aim to identify the molecular mechanisms underlying Tpm3.1 targeting to different subcellular compartments.

scholarly journals Prostacyclin-IP signaling and prostaglandin E2-EP2/EP4 signaling both mediate joint inflammation in mouse collagen-induced arthritis

2006 ◽  
Vol 203 (2) ◽  
pp. 325-335 ◽  
Author(s):  
Tetsuya Honda ◽  
Eri Segi-Nishida ◽  
Yoshiki Miyachi ◽  
Shuh Narumiya
Keyword(s):  
Rheumatoid Arthritis ◽  
Synovial Fluid ◽  
Joint Inflammation ◽  
Synovial Fibroblasts ◽  
The Other ◽  
Receptor Subtype ◽  
Significant Suppression ◽  
Wild Type ◽  
Collagen Induced Arthritis

Prostaglandin (PG)I2 (prostacyclin [PGI]) and PGE2 are abundantly present in the synovial fluid of rheumatoid arthritis (RA) patients. Although the role of PGE2 in RA has been well studied, how much PGI2 contributes to RA is little known. To examine this issue, we backcrossed mice lacking the PGI receptor (IP) to the DBA/1J strain and subjected them to collagen-induced arthritis (CIA). IP-deficient (IP−/−) mice exhibited significant reduction in arthritic scores compared with wild-type (WT) mice, despite anti-collagen antibody production and complement activation similar to WT mice. IP−/− mice also showed significant reduction in contents of proinflammatory cytokines, such as interleukin (IL)-6 in arthritic paws. Consistently, the addition of an IP agonist to cultured synovial fibroblasts significantly enhanced IL-6 production and induced expression of other arthritis-related genes. On the other hand, loss or inhibition of each PGE receptor subtype alone did not affect elicitation of inflammation in CIA. However, a partial but significant suppression of CIA was achieved by the combined inhibition of EP2 and EP4. Our results show significant roles of both PGI2-IP and PGE2-EP2/EP4 signaling in the development of CIA, and suggest that inhibition of PGE2 synthesis alone may not be sufficient for suppression of RA symptoms.

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