Flavoenzyme CrmK-mediated substrate recycling in caerulomycin biosynthesis.

Substrate salvage or recycling is common and important for primary metabolism in cells but is rare in secondary metabolism. Herein we report flavoenzyme CrmK-mediated shunt product recycling in the biosynthesis of caerulomycin A (CRM A ), a 2,2'-bipyridine-containing natural product that is under development as a potent novel immunosuppressive agent. We demonstrated that the alcohol oxidase CrmK, belonging to the family of bicovalent FAD-binding flavoproteins, catalyzed the conversion of an alcohol into a carboxylate an aldehyde.

Structure, Dynamics, and Interaction of p54(nrb)/NonO RRM1 with 5' Splice Site RNA Sequence.

p54(nrb)/NonO is a nuclear RNA-binding protein involved in many cellular events such as pre-mRNA processing, transcription, and nuclear retention of hyper-edited RNAs. In particular, it participates in the splicing process by directly binding the 5' splice site of pre-mRNAs. The protein also concentrates in a nuclear body called paraspeckle by binding a G-rich segment of the ncRNA NEAT1.

Fludarabine downregulates indoleamine 2,3-dioxygenase in tumors via a proteasome-mediated degradation mechanism.

Indoleamine 2,3-dioxygenase (IDO) is found in multiple malignancies and exerts immunosuppressive effects that are central in protecting tumors from host T lymphocyte rejection. IDO is an enzyme involved in the catabolism of tryptophan resulting in inhibition of T lymphocyte function. While inhibition of IDO enzymatic activity results in tumor rejection, it is still unknown how we can directly target IDO expression within tumors using drugs.

Interfering with hepatitis C virus assembly in vitro using affinity peptides directed towards core protein.

Viral assembly is a crucial key step in the life cycle of every virus. In the case of Hepatitis C virus (HCV), the core protein is the only structural protein to interact directly with the viral genomic RNA. Purified recombinant core protein is able to self-assemble in vitro into nucleocapsid-like particles upon addition of a structured RNA, providing a robust assay with which to study HCV assembly.

IDO expression by human B lymphocytes in response to T lymphocyte stimuli and TLR engagement is biologically inactive.

The immune system must be under tight control to avoid undesired responses. The enzyme indoleamine 2,3-dioxygenase (IDO) can exert necessary regulating effects by catabolizing tryptophan, leading to the suppression of immune responses in different settings, such as pregnancy and tumor growth. IDO's immuno-suppressive actions are mediated by tryptophan starvation and the accumulation of toxic tryptophan metabolites, resulting in T cell anergy, inhibition of clonal expansion or apoptosis.

Structure and dynamics changes induced by 2,2,2-trifluoro-ethanol (TFE) on the N-terminal half of hepatitis C virus core protein.

The Core protein of hepatitis C virus is involved in several interactions other than the encapsidation of viral RNA. We recently proposed that this is related to the fact that the N-terminal half of this protein (C82) is an intrinsically unstructured protein (IUP) domain. IUP domains can adopt a secondary structure when they are interacting with another molecule, such as a nucleic acid or a protein.

Structure and dynamics of the N-terminal half of hepatitis C virus core protein: an intrinsically unstructured protein.

Hepatitis C virus core protein plays an important role in the assembly and packaging of the viral genome. We have studied the structure of the N-terminal half of the core protein (C82) which was shown to be sufficient for the formation of nucleocapsid-like particle (NLP) in vitro and in yeast. Structural bioinformatics analysis of C82 suggests that it is mostly unstructured.

A method for in vitro assembly of hepatitis C virus core protein and for screening of inhibitors.

The assembly of hepatitis C virus (HCV) is not well understood. We investigated HCV nucleocapsid assembly in vitro and the role of electrostatic/hydrophobic interactions in this process. We developed a simple and rapid in vitro assay in which the progress of assembly is monitored by measuring an increase in turbidity, thereby allowing the kinetics of assembly to be determined.

Effect of cAMP-dependent protein kinase A (PKA) on HCV nucleocapsid assembly and degradation.

The primary function of the hepatitis C virus (HCV) core protein is genome encapsidation. Core protein is also subject to post-translational modifications that can impact on the assembly process. In this report, we have studied the effect of cAMP-dependent protein kinase A (PKA) phosphorylation on its assembly and stability in a yeast Pichia pastoris expression system.

Effect of mutations K97A and E128A on RNA binding and self assembly of papaya mosaic potexvirus coat protein.

Papaya mosaic potexvirus (PapMV) coat protein (CP) was expressed (CPdeltaN5) in Escherichia coli and showed to self assemble into nucleocapsid like particles (NLPs). Twenty per cent of the purified protein was found as NLPs of 50 nm in length and 80% was found as a multimer of 450 kDa (20 subunits) arranged in a disk. Two mutants in the RNA binding domain of the PapMV CP, K97A and E128A showed interesting properties.