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Gilles Truan

Publications and source records attributed to Gilles Truan.

6 recordsLinked to original sources
PubMed2006

A combinatorial approach to substrate discrimination in the P450 CYP1A subfamily.

A comparison of all known mammalian CYP1A sequences identifies nineteen sequence regions that are conserved within all 1A1s or within all 1A2s but at the same time systematically differ between any 1A1 and any 1A2. The purpose of this study was to explore links between these specific CYP1A sequence signatures and substrate specificity shift through the kinetic analysis of combinatorial variants of increasing complexity. The less complex variants correspond to multiple mutations within a short segment of their sequence. The more complex variants correspond to mosaic P450s recombining 1A1 and 1A2 sequences (up to 5 crossovers per sequence). Fifty-eight such functional CYP1A variants and parental wild-type enzymes were expressed in yeast and assayed with 7-alkoxyresorufins and ethoxyflurorescein ethyl ester as substrates. Observed kinetic data were analyzed by multivariate statistical analyses and hierarchical clustering in order to highlight correlations and identify potential sequence-activity relationships within the three-dimensional function space investigated. Several variants are outliers in these representations and show a redistribution of their substrate specificity compared to wild-type CYP1As. Some combinations of sequence elements were identified that significantly discriminate between 1A1 and 1A2 for these three substrates. The comparison of this combinatorial approach with previous results of site-directed mutagenesis is discussed.

Amino Acid Sequence↗
PubMed2004

Gene2Oligo: oligonucleotide design for in vitro gene synthesis.

There is substantial interest in implementing a bioinformatics tool that allows the design of oligonucleotides to support the development of in vitro gene synthesis. Current protocols to make long synthetic DNA molecules rely on the in vitro assembly of a set of short oligonucleotides, either by ligase chain reaction (LCR) or by assembly PCR. Ideally, such oligonucleotides should represent both strands of the final DNA molecule. They should be adjacent on the same strand and overlap the complementary oligonucleotides from the second strand to ensure good hybridization during assembly. This implies that the thermodynamic properties of each oligonucleotide have to be consistent across the set. Furthermore, any given oligonucleotide has to be totally specific to its target to avoid the creation of incorrectly assembled sequences. We have developed Gene2Oligo (http://berry.engin.umich.edu/gene2oligo/), a web-based tool that divides a long input DNA sequence into a set of adjacent oligonucleotides representing both DNA strands. The length of the oligonucleotides is dynamically optimized to ensure both the specificity and the uniform melting temperatures necessary for in vitro gene synthesis. We have successfully designed and used a set of oligonucleotides to synthesize the Saccharomyces cerevisiae cytochrome b5 by using both LCR and assembly PCR.

Algorithms↗
PubMed2003

Computational methods for sequence mapping of large combinatorial libraries and deduced sequence signatures.

Here we describe a computational approach for the high-throughput sequence mapping of combinatorial libraries obtained by DNA shuffling. Original algorithms and their software implementation were developed for the automated and reliable analysis of hybridization data of differentially labeled oligonucleotide probes with PCR products spotted on DNA microarrays. This novel approach allows a context-dependent sequence attribution tolerant to fluctuations in experimental conditions and is well adapted to hybridization signals of variable qualities resulting from high-throughput PCR amplification from colonies. In addition, the analysis permits the calculation of sequence signatures that are characteristic of combinatorial library structure, defects, and diversity. The approach is of interest for the characterization and the equalization (library reduction to nonredundant structures) of combinatorial libraries involved in directed evolution and could be extrapolated to high-throughput polymorphism analysis.

Biotechnology↗