Search PubMed⌕ Search

Biomedical subjects

Leodevico L Ilag

Publications and source records attributed to Leodevico L Ilag.

8 recordsLinked to original sources
PubMed2003

Direct methods for modulating protein function.

During the past few years, the drug discovery process has shifted from a chemistry- to a biology-driven paradigm. Genome sciences have made a significant contribution to this shift, leading to a plethora of potential drug targets that are mainly proteins. Genetic methods will continue to be used to characterize proteins, but more direct methods are needed to determine the suitability of these protein targets for pharmacological intervention. In addition to the use of antibodies and aptamers, technologies focusing on the direct modulation of protein activity, including chemical genetics, analog-sensitive enzyme alleles and chromophore-assisted laser inactivation, should significantly contribute to the field of post-genomic drug discovery and development.

Animals↗
PubMed2002

Emerging high-throughput drug target validation technologies.

Identifying the right target for drug development is a critical bottleneck in the pharmaceutical and biotech industries. The genomics revolution has shifted the problem from a scarcity of targets to a surplus of putative drug targets. As the validity of a target cannot be simply inferred from correlative data, the key is confirmation of the causative role of a gene product in a particular disease. It should therefore be recognized that an effective therapeutic strategy requires an appropriate target validation technology to verify the right target.

Biotechnology↗
PubMed2002

Functional proteomics using chromophore-assisted laser inactivation.

Proteins are the molecules that fulfil most cellular functions and represent over 90% of drug targets in the market. Chromophore-assisted laser inactivation (CALI) provides a timely and locally restricted protein inactivation and has proven to specifically destroy protein function using dye-coupled ligands and laser irradiation. CALI involves the generation of short-lived radicals thus limiting the radius of covalent modifications to spatially restricted sites on the target molecule. A transient functional inactivation occurs if the radicals modify amino acids of the target protein that are responsible for function. Here we show specific inactivation of several protein targets, that are members of relevant signal transduction pathways. For each of these targets, simple and high throughput screening-scaleable assays have been developed, making it possible to quantify the observed inactivation. Activities of target proteins have been addressed in cell-free as well as cell-based assays employing human primary and tumor-derived cell lines. In all cases, at least 50% inactivation was achieved. The data presented here demonstrate that CALI is a highly versatile tool for validating disease relevant targets at the protein level. This approach also takes into account post-translational modifications like phosphorylation, glycosylation or acylation, thereby enlarging its applicability for many different types of targets.

Apoptosis↗
PubMed2002

From patenting genes to proteins: the search for utility via function.

The debate regarding the patenting of genes has extended into the post-genome era. With only approximately 35000 genes deduced from the draft sequence of the human genome, there are fears that a few companies have already gained monopoly on the potential benefits from this knowledge. Nevertheless, it is accepted that proteins determine gene function and function is not readily predicted from gene sequence. Furthermore, genes can encode multiple proteins and a single protein can have multiple functions. Here, we argue that unraveling the intrinsic complexity of proteins and their functions is the key towards determining the utility requirement for patenting protein inventions and consider the possible socioeconomic impact.

DNA↗
PubMed1995

DNA packaging intermediates of bacteriophage φX174

BACKGROUND: Like many viruses, bacteriophage phi X174 packages its DNA genome into a procapsid that is assembled from structural intermediates and scaffolding proteins. The procapsid contains the structural proteins F, G and H, as well as the scaffolding proteins B and D. Provirions are formed by packaging of DNA together with the small internal J proteins, while losing at least some of the B scaffolding proteins. Eventually, loss of the D scaffolding proteins and the remaining B proteins leads to the formation of mature virions. RESULTS: phi X174 108S 'procapsids' have been purified in milligram quantities by removing 114S (mature virion) and 70S (abortive capsid) particles from crude lysates by differential precipitation with polyethylene glycol. 132S 'provirions' were purified on sucrose gradients in the presence of EDTA. Cryo-electron microscopy (cryo-EM) was used to obtain reconstructions of procapsids and provirions. Although these are very similar to each other, their structures differ greatly from that of the virion. The F and G proteins, whose atomic structures in virions were previously determined from X-ray crystallography, were fitted into the cryo-EM reconstructions. This showed that the pentamer of G proteins on each five-fold vertex changes its conformation only slightly during DNA packaging and maturation, whereas major tertiary and quaternary structural changes occur in the F protein. The procapsids and provirions were found to contain 120 copies of the D protein arranged as tetramers on the two-fold axes. DNA might enter procapsids through one of the 30 A diameter holes on the icosahedral three-fold axes. CONCLUSIONS: Combining cryo-EM image reconstruction and X-ray crystallography has revealed the major conformational changes that can occur in viral assembly. The function of the scaffolding proteins may be, in part, to support weak interactions between the structural proteins in the procapsids and to cover surfaces that are subsequently required for subunit-subunit interaction in the virion. The structures presented here are, therefore, analogous to chaperone proteins complexed with folding intermediates of a substrate.

Bacteriophage phi X 174↗
PubMedDate not supplied

Biomedical applications of protein chips.

The development of microchips involving proteins has accelerated within the past few years. Although DNA chip technologies formed the precedent, many different strategies and technologies have been used because proteins are inherently a more complex type of molecule. This review covers the various biomedical applications of protein chips in diagnostics, drug screening and testing, disease monitoring, drug discovery (proteomics), and medical research. The proteomics and drug discovery section is further subdivided to cover drug discovery tools (on-chip separations, expression profiling, and antibody arrays), molecular interactions and signaling pathways, the identification of protein function, and the identification of novel therapeutic compounds. Although largely focused on protein chips, this review includes chips involving cells and tissues as a logical extension of the type of data that can be generated from these microchips.

Animals↗