Gisele Cardoso Amorim

Federal University of Rio de Janeiro | UFRJ · Núcleo Multidisciplinar de Pesquisa em Biologia/XERÉM

Protein folding, refolding and disaggregation are facilitated by the binding and releasing activity of HSP70 proteins. Such activity is aided by J-domain proteins (JDPs, DNAJs or HSP40s) that stimulate the ATPase activity of HSP70 and stabilize complexes between HSP70 and nonnative proteins. The C-terminus EEVD motif of HSP70 interacts with client...

ExbB and ExbD are cytoplasmic membrane proteins that associate with TonB to convey the energy of the proton-motive force to outer membrane receptors in Gram-negative bacteria for iron uptake. The opportunistic pathogen Serratia marcescens (Sm) possesses both TonB and a heme-specific TonB paralog, HasB. ExbBSm has a long periplasmic extension absent...

Klebsiella pneumoniae is an opportunistic pathogen, which concerns public health systems worldwide, as multiple antibiotic‐resistant strains are frequent. One of its pathogenicity factors is the Type VI Secretion System (T6SS), a macromolecular complex assembled through the bacterial membranes. T6SS injects effector proteins inside target cells. Su...

The SARS-CoV-2 nucleocapsid protein (N) is a multifunctional promiscuous nucleic acid-binding protein, which plays a major role in nucleocapsid assembly and discontinuous RNA transcription, facilitating the template switch of transcriptional regulatory sequences (TRS). Here, we dissect the structural features of the N protein N-terminal domain (N-N...

The SARS-CoV-2 nucleocapsid protein (N) is a multifunctional promiscuous nucleic acid-binding protein, which plays a major role in nucleocapsid assembly and discontinuous RNA transcription, facilitating the template switch of transcriptional regulatory sequences (TRS). Here, we dissect the structural features of the N protein N-terminal domain (N-N...

Tumor lysis syndrome (TLS) is a metabolic disorder that mainly affects patients with malignant hematological neoplasms, and its development is frequently related to uric acid accumulation (hyperuricemia). Rasburicase is a recom-binant urate oxidase enzyme applied to treat and avoid TLS converting urate into allantoin, a compound easily eliminated b...

The highly infectious disease COVID-19 caused by the Betacoronavirus SARS-CoV-2 poses a severe threat to humanity and demands the redirection of scientific efforts and criteria to organized research projects. The international COVID19-NMR consortium seeks to provide such new approaches by gathering scientific expertise worldwide. In particular, mak...

Coronaviruses have become of great medical and scientific interest because of the Covid-19 pandemic. The hCoV-HKU1 is an endemic betacoronavirus that causes mild respiratory symptoms, although the infection can progress to severe lung disease and death. During viral replication, a discontinuous transcription of the genome takes place, producing the...

Bacterial type 4a pili are dynamic surface filaments that promote bacterial adherence, motility and macromolecular transport. Their genes are highly conserved amongst enterobacteria and their expression in Enterohemorrhagic Escherichia coli (EHEC) promotes adhesion to intestinal epithelia and pro-inflammatory signaling. To define the molecular basi...

J-domain/Hsp40 proteins cooperate in aiding with folding in the cell by binding partially folded client proteins and delivering them to be folded by Hsp70. The delivery occurs concomitantly to the stimulation of the ATPase activity of Hsp70 via the N-terminally located J-domain. Although several lines of investigation have been used to study J-doma...

Massive lysis of tumor mass in cancer patients under chemotherapy regimens generates high levels of uric acid, leading to what is known as tumor lysis syndrome (TLS). Rasburicase, a recombinant urate oxidase, converts urate to allantoin, which is readily excreted by the kidneys. Even though there is a high production of allantoin from urate in canc...

Protein folding in the cell is usually aided by molecular chaperones, from which the Hsp70 (Hsp = heat shock protein) family has many important roles, such as aiding nascent folding and participating in translocation. Hsp70 has ATPase activity which is stimulated by binding to the J-domain present in co-chaperones from the Hsp40 family. Hsp40s have...

Bacteria use diverse signaling pathways to adapt gene expression to external stimuli. In Gram-negative bacteria, the binding of scarce nutrients to membrane transporters triggers a signaling process that upregulates the expression of genes of various functions, from uptake of nutrient to production of virulence factors. Although proteins involved i...

Bacteria use diverse signaling pathways to control gene expression in response to external stimuli. In Gram-negative bacteria, the binding of a nutrient is sensed by an outer membrane transporter. This signal is then transmitted to an antisigma factor and subsequently to the cytoplasm where an ECF sigma factor induces expression of genes related to...

TonB is a key protein in active transport of essential nutrients like vitamin B12 and metal sources through the outer membrane transporters of Gram-negative bacteria. This inner membrane protein spans the periplasm, contacts the outer membrane receptor by its periplasmic domain and transduces energy from the cytoplasmic membrane pmf to the receptor...

Topology cartoons representing HasBCTD (2M2K) and its structural neighbors, TolA (1LR0) and TonB (1XX3). The figure was drawn using TopDraw. (TIF)

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ITC analysis of the interaction of TonBCTD with the dodecamer peptide. Representative experiment is shown. The heat signal (top) is presented together with the binding isotherm derived from the signal (bottom). (TIF)

Bacterial type 4 pili (T4P) are long flexible fibers involved in adhesion, DNA uptake, phage transduction, aggregation and a flagella-independent movement called “twitching motility”. T4P comprise thousands of copies of the major pilin subunit, which is initially inserted in the plasma membrane, processed and assembled into dynamic helical filament...

TonB-dependent transporters (TBDTs) are bacterial outer membrane proteins that internalize nutrients such as vitamin B12, metal complexes, heme, some carbohydrates, etc. In addition to their transport activity, several TBDTs are also involved in a signalling cascade from the cell surface into the cytoplasm, via their periplasmic signalling domain....

Keywords NMR Saccharomyces cerevisiae Structure Thioredoxin 2 YeastAbbreviationsTrx thioredoxinBiological contextThioredoxins (Trxs) are ubiquitous heat-stable pro-teins of molecular mass approximately 12,000 Da thatfunction as dithiol oxidoreductases, and are impor-tant for cellular defense against oxidative stress(Monje-Casas et al. 2004). Trxs a...

Nuclear magnetic resonance is an important tool for high-resolution structural studies of proteins. It demands high protein concentration and high purity; however, the expression of proteins at high levels often leads to protein aggregation and the protein purification step can correspond to a high percentage of the overall time in the structural d...