scholarly journals Identification of a pro-inhibitory region on the surface of human CYP1A2

1995 ◽  
Vol 78 ◽  
pp. 16
Author(s):  
D.A. Adams ◽  
R.J. Edwards ◽  
A.R. Boobis
Keyword(s):  
Inhibitory Region ◽  
Human Cyp1a2

scholarly journals An antisense noncoding RNA enhances translation via localised structural rearrangements of its cognate mRNA

2021 ◽  
Author(s):  
Rodrigo S Reis ◽  
Jules Deforges ◽  
Romy R Schmidt ◽  
Jos H M Schippers ◽  
Yves Poirier
Keyword(s):  
Antisense Rna ◽  
Noncoding Rna ◽  
Regulatory Region ◽  
Structural Rearrangement ◽  
Start Codon ◽  
Structural Rearrangements ◽  
Eukaryotic Genes ◽  
Inhibitory Region ◽  
Rna Interaction

Abstract A large portion of eukaryotic genes are associated with noncoding, natural antisense transcripts (NATs). Despite sharing extensive sequence complementarity with their sense mRNAs, mRNA-NAT pairs elusively often evade dsRNA-cleavage and siRNA-triggered silencing. More surprisingly, some NATs enhance translation of their sense mRNAs by yet unknown mechanism(s). Here we show that translation enhancement of the rice (Oryza sativa) PHOSPHATE1.2 (PHO1.2) mRNA is enabled by specific structural rearrangements guided by its noncoding antisense RNA (cis-NATpho1.2). Their interaction in vitro revealed no evidence of widespread intermolecular dsRNA formation, but rather specific local changes in nucleotide base-pairing, leading to higher flexibility of PHO1.2 mRNA at a key high GC regulatory region inhibiting translation, approximately 350 nucleotides downstream of the start codon. Sense-antisense RNA interaction increased formation of the 80S complex in PHO1.2, possibly by inducing structural rearrangement within this inhibitory region, thus making this mRNA more accessible to 60S. This work presents a framework for nucleotide-resolution studies of functional mRNA-antisense pairs. One-sentence summary: Interaction between PHO1.2 mRNA and its cis-natural antisense transcript enhances translation via a mechanism involving a local conformational shift and disruption of a key inhibitory region.

Calmodulin and troponin C: affinity chromatographic study of divalent cation requirements for troponin I inhibitory peptide (residues 104–115), mastoparan, and fluphenazine binding

1987 ◽  
Vol 65 (11) ◽  
pp. 982-988 ◽  
Author(s):  
Jennifer E. Van Eyk ◽  
Robert S. Hodges
Keyword(s):  
Troponin I ◽  
Troponin C ◽  
Homologous Region ◽  
Affinity Column ◽  
Chromatographic Study ◽  
Inhibitory Peptide ◽  
Receptor Sites ◽  
Inhibitory Region ◽  
Correct Alignment ◽  
Correct Structure

The different conformations induced by the binding of Mg2+ or Ca2+ to troponin C (TnC) and calmodulin (CaM) results in the exposure of various interfaces with potential to bind target compounds. The interaction of TnC or CaM with three affinity columns with ligands of either the synthetic peptide of troponin I (TnI) inhibitory region (residues 104–115), mastoparan (a wasp venom peptide), or fluphenazine (a phenothiazine drug) were investigated in the presence of Mg2+ or Ca2+. TnC and CaM in the presence of either Ca2+ or Mg2+ bound to the TnI peptide 104–115. The cation specificity for this interaction firmly establishes that the TnI inhibitory region binds to the high affinity sites of TnC (most likely the N-terminal helix of site III) and presumably the homologous region of CaM. Mastoparan interacted strongly with both proteins in the presence of Ca2+ but, in the presence of Mg2+, did not bind to TnC and only bound weakly to CaM. Fluphenazine bound to TnC and CaM only in the presence of Ca2+. When the ligands interacted with either proteins there was an increase in cation affinity, such that TnC and CaM were eluted from the TnI peptide or mastoparan affinity column with 0.1 M EDTA compared with the 0.01 M EDTA required to elute the proteins from the fluphenazine column. The interaction of these ligands with their receptor sites on TnC and CaM require a specific and spatially correct alignment of hydrophobic and negatively charged residues on these proteins. In the case of the TnI peptide, which represents a naturally occurring target protein for TnC, Mg2+ and Ca2+ can induce the correct structure in TnC or CaM for interaction, while only Ca2+ can induce the correct structure for mastoparan or fluophenazine binding.

scholarly journals Inhibitory effects of antiarrhythmic drugs on phenacetin O‐deethylation catalysed by human CYP1A2

1998 ◽  
Vol 45 (4) ◽  
pp. 361-368 ◽  
Author(s):  
K. Kobayashi ◽  
M. Nakajima ◽  
K. Chiba ◽  
T. Yamamoto ◽  
M. Tani ◽  
...  
Keyword(s):  
Antiarrhythmic Drugs ◽  
Inhibitory Effects ◽  
Human Cyp1a2

New mimetic peptides of the kinase-inhibitory region (KIR) of SOCS1 through focused peptide libraries

2012 ◽  
Vol 443 (1) ◽  
pp. 231-240 ◽  
Author(s):  
Nunzianna Doti ◽  
Pasqualina L. Scognamiglio ◽  
Stefania Madonna ◽  
Claudia Scarponi ◽  
Menotti Ruvo ◽  
...  
Keyword(s):  
Interferon Γ ◽  
Catalytic Site ◽  
Janus Kinase ◽  
Scanning Method ◽  
Expression Levels ◽  
Interferon Regulatory Factor 1 ◽  
Inhibitory Region ◽  
Inflammatory Processes ◽  
Cytokine Stimulation ◽  
Kinase Inhibitory Region

SOCS (suppressor of cytokine signalling) proteins are negative-feedback regulators of the JAK (Janus kinase)/STAT (signal transducer and activator of transcription) pathway. Their expression levels are low under physiological conditions, but they are up-regulated in response to cytokine stimulation in many immune and inflammatory processes. Overexpression of SOCS1 in keratinocyte clones abrogates the IFNγ (interferon γ)-induced expression of many pro-inflammatory genes and the release of related chemokines by blocking the JAK/STAT pathway. SOCS1 inhibits JAK2 kinase activity by binding the catalytic site of JAK2, with its KIR (kinase-inhibitory region) acting as a pseudo-substrate of the enzyme. In the present study, we screened a focused combinatorial peptide library of KIR to identify new peptides able to mimic its function with an improved affinity towards the JAK2 catalytic site. Using an alanine-scanning method, KIR residues that are crucial for the interaction with JAK2 were unveiled. In this way, the KIR sequence was restricted to a shorter segment and ‘non-essential’ residues were replaced by different amino acids following a simplified combinatorial approach. We selected a new unnatural sequence able to bind to JAK2 with Kd values in the nanomolar range. This peptide was tested in human keratinocyte cultures and reduced the phosphorylation of STAT1 and the expression levels of IRF-1 (interferon regulatory factor-1).

scholarly journals Functional analysis of Met4, a yeast transcriptional activator responsive to S-adenosylmethionine.

1995 ◽  
Vol 15 (1) ◽  
pp. 208-216 ◽  
Author(s):  
L Kuras ◽  
D Thomas
Keyword(s):  
Transcriptional Activation ◽  
Leucine Zipper ◽  
Transcriptional Activator ◽  
Activation Function ◽  
Functional Domain ◽  
Distinct Region ◽  
Activation Domain ◽  
Inhibitory Region ◽  
Leucine Zipper Protein ◽  
Basic Region

Transcription of the genes necessary for sulfur amino acid biosynthesis in Saccharomyces cerevisiae is dependent on Met4, a transcriptional activator that belongs to the basic region-leucine zipper protein family. In this report, we show that one mechanism permitting the repression of the sulfur network by S-adenosylmethionine (AdoMet) involves inhibition of the transcriptional activation function of Met4. Using a wide array of deleted LexA-Met4 fusion proteins as well as various Gal4-Met4 hybrids, we identify the functional domains of Met4 and characterize their relationship. Met4 appears to contain only one activation domain, located in its N-terminal part. We demonstrate that this activation domain functions in a constitutive manner and that AdoMet responsiveness requires a distinct region of Met4. Furthermore, we show that when fused to a heterologous activation domain, this inhibitory region confers inhibition by AdoMet. Met4 contains another distinct functional domain that appears to function as an antagonist of the inhibitory region when intracellular AdoMet is low. On the basis of the presented results, a model for intramolecular regulation of Met4 is proposed.

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