Chemistry and Modelling for Protein Recognition

Team Publications

Year of publication 2009

François Besselièvre, Sabrina Lebrequier, Florence Mahuteau-Betzer, Sandrine Piguel (2009 Sep 3)

C-H Bond Activation: A Versatile Protocol for the Direct Arylation and Alkenylation of Oxazoles

Synthesis : 2009 : 3511-3518 : DOI : 10.1055/s-0029-1216987 Learn more
Summary

The versatile palladium complex Pd(PPh3)4 catalyses both direct arylation and alkenylation of oxazoles efficiently. The method is regioselective and stereospecific with respect to bromoalkenes and tolerates a wide range of functional groups.

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Ibrahima Diallo, Nadia Haddy, Elisabeth Adjadj, Akhtar Samand, Eric Quiniou, Jean Chavaudra, Iannis Alziar, Nathalie Perret, Sylvie Guérin, Dimitri Lefkopoulos, Florent de Vathaire (2009 Apr 24)

Frequency distribution of second solid cancer locations in relation to the irradiated volume among 115 patients treated for childhood cancer.

International journal of radiation oncology, biology, physics : 74 : 876-883 : DOI : 10.1016/j.ijrobp.2009.01.040 Learn more
Summary

PURPOSE:

To provide better estimates of the frequency distribution of second malignant neoplasm (SMN) sites in relation to previous irradiated volumes, and better estimates of the doses delivered to these sites during radiotherapy (RT) of the first malignant neoplasm (FMN).

METHODS AND MATERIALS:

The study focused on 115 patients who developed a solid SMN among a cohort of 4581 individuals. The homemade software package Dos_EG was used to estimate the radiation doses delivered to SMN sites during RT of the FMN. Three-dimensional geometry was used to evaluate the distances between the irradiated volume, for RT delivered to each FMN, and the site of the subsequent SMN.

RESULTS:

The spatial distribution of SMN relative to the irradiated volumes in our cohort was as follows: 12% in the central area of the irradiated volume, which corresponds to the planning target volume (PTV), 66% in the beam-bordering region (i.e., the area surrounding the PTV), and 22% in regions located more than 5 cm from the irradiated volume. At the SMN site, all dose levels ranging from almost zero to >75 Gy were represented. A peak SMN frequency of approximately 31% was identified in volumes that received <2.5 Gy.

CONCLUSION:

A greater volume of tissues receives low or intermediate doses in regions bordering the irradiated volume with modern multiple-beam RT arrangements. These results should be considered for risk-benefit evaluations of RT.

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Liliane Mouawad, Adriana Isvoran, Eric Quiniou, Constantin T Craescu (2009 Jan 22)

What determines the degree of compactness of a calcium-binding protein?

The FEBS journal : 276 : 1082-1093 : DOI : 10.1111/j.1742-4658.2008.06851.x Learn more
Summary

The EF-hand calcium-binding proteins may exist either in an extended or a compact conformation. This conformation is sometimes correlated with the function of the calcium-binding protein. For those proteins whose structure and function are known, calcium sensors are usually extended and calcium buffers compact; hence, there is interest in predicting the form of the protein starting from its sequence. In the present study, we used two different procedures: one that already exists in the literature, the sosuidumbbell algorithm, mainly based on the charges of the two EF-hand domains, and the other comprising a novel procedure that is based on linker average hydrophilicity. The linker consists of the residues that connect the domains. The two procedures were tested on 17 known-structure calcium-binding proteins and then applied to 59 unknown-structure centrins. The sosuidumbbell algorithm yielded the correct conformations for only 15 of the known-structure proteins and predicted that all centrins should be in a closed form. The linker average hydrophilicity procedure discriminated well between all the extended and non-extended forms of the known-structure calcium-binding proteins, and its prediction concerning centrins reflected well their phylogenetic classification. The linker average hydrophilicity criterion is a simple and powerful means to discriminate between extended and non-extended forms of calcium-binding proteins. What is remarkable is that only a few residues that constitute the linker (between 2 and 20 in our tested sample of proteins) are responsible for the form of the calcium-binding protein, showing that this form is mainly governed by short-range interactions.

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Year of publication 2008

Besselièvre F., Piguel S., Mahuteau-Betzer F., Grierson D.S. (2008 Aug 23)

Stereoselective Direct Copper-Catalyzed Alkenylation of Oxazoles with Bromoalkenes

Organic Letters : 10 : 4029-4032 : DOI : 10.1021/ol801512q Learn more
Summary

A copper-catalyzed direct alkenylation of oxazoles with bromoalkenes has been developed. The method is both regio- and stereoselective and tolerates a variety of functional groups. A wide range of 2-E-vinyl-substituted oxazoles were obtained in high yields including the highly fluorescent alkaloid annuloline.

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François Besselièvre, Florence Mahuteau-Betzer, David S Grierson, Sandrine Piguel (2008 Mar 20)

Ligandless microwave-assisted Pd/Cu-catalyzed direct arylation of oxazoles

The Journal of organic chemistry : 3278-3280 : DOI : 10.1021/jo7027135 Learn more
Summary

An efficient microwave-assisted palladium/copper co-mediated direct arylation of oxazoles with aryl bromides under ligandless conditions has been developed. The method is functional group tolerant and provides rapid access to medicinally relevant compounds in good yields. Coupled to the van Leusen oxazole ring synthesis, this methodology is illustrated by an expedient two-step synthesis of the four 2,5-diaryloxazole alkaloids texamine, texaline, balsoxin, and O-Me-halfordinol from commercially available starting materials.

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Year of publication 2005

A Dupuy, A Shamsaldin, E Quiniou, C Paoletti, M Labbé, M F Avril, D Lefkopoulos, F de Vathaire (2005 Oct 26)

Risk of melanoma following adulthood cancer: a case-control study.

European journal of cancer (Oxford, England : 1990) : 41 : 2904-2910 : DOI : 10.1016/j.ejca.2005.07.020 Learn more
Summary

Melanoma is a severe skin cancer related to sun exposure. Whether this malignancy is linked to exposure to ionising radiation during adulthood is still controversial. This case-control study examined the risk of melanoma following treatment for an adulthood first malignant neoplasm (FMN). Cases were patients who presented with cutaneous melanoma after a first cancer in adulthood. Controls (3 per case) were patients free of melanoma, matched for age, duration of follow-up since the FMN, type of FMN, and followed in the same institution. A total of 57 cases and 171 controls were included. In the final multivariate analysis, no risk of melanoma was associated with radiotherapy (odds ratio (OR) for 1 Gy = 1.01, 95% confidence interval (95%CI) 0.96-1.07) nor hormonotherapy, whereas chemotherapy use (OR = 2.3, 95%CI 0.93-5.6) and having a history of familial cancer (OR = 2.8, 95%CI 1.3-5.9) exhibited a nearly significant risk. In conclusion, unlike the evidence for risk of exposure to ionising radiation during childhood, we did not substantiate a risk for association of melanoma with exposure to ionising radiation during adulthood. The risk associated with chemotherapy should justify the implementation of skin surveillance for early detection of melanoma in these patients.

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Year of publication 2003

Catherine Tetreau, Yves Blouquit, Eugene Novikov, Eric Quiniou, Daniel Lavalette (2003 Dec 26)

Competition with xenon elicits ligand migration and escape pathways in myoglobin.

Biophysical journal : 86 : 435-447 : DOI : 10.1016/S0006-3495(04)74120-X Learn more
Summary

Evidence for ligand migration toward the xenon-binding cavities in myoglobin comes from a number of laser photolysis studies of MbO2 including mutants and from cryo- and time-resolved crystallography of MbCO. To explore ligand migration in greater detail, we investigated the rebinding kinetics of both MbO2 and MbCO under a xenon partial pressure ranging from 1 to 16 atm over the temperature range (293-77 K). Below 180 K xenon affects to a significant, but minor, extent the thermodynamic parameters for rebinding from the primary docking site in each Mb taxonomic substate. Above 200 K the ligand migrates to the proximal Xe1 site but when the latter is occupied by xenon a new kinetic process appears. It is attributed to rebinding from transient docking sites located on the path between the primary and the secondary docking site of both ligands. Ligand escape exhibits a more complicated pattern than expected. At room temperature O2 and CO escape appears to take place exclusively from the primary site. In contrast, at T approximately 250 K, roughly 50% of the CO molecules that have escaped from the protein originate from the Xe1 secondary site.

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S Guérin, A Dupuy, H Anderson, A Shamsaldin, G Svahn-Tapper, T Moller, E Quiniou, S Garwicz, M Hawkins, M F Avril, O Oberlin, J Chavaudra, F de Vathaire (2003 Oct 15)

Radiation dose as a risk factor for malignant melanoma following childhood cancer.

European journal of cancer (Oxford, England : 1990) : 39 : 2379-86 : DOI : 10.1016/S0959-8049(03)00663-4 Learn more
Summary

The aim of this study was to determine therapy-related risk factors for the development of melanoma after childhood cancer. Among 4401 3-year survivors of a childhood cancer in eight French and British centres and 25120 patients younger than 20 years old at first malignant neoplasm (FMN) extracted from the Nordic Cancer Registries, 16 patients developed a melanoma as a second malignant neoplasm (SMN). A cohort study of the French and British cohorts was performed. In a nested case-control study, the 16 patients who developed a melanoma as a SMN (cases) were matched with 3-5 controls in their respective cohort according to gender, age at the first cancer, the calendar year of occurrence of the first cancer and follow-up. Radiotherapy appeared to increase the risk of melanoma for local doses >15 Gy, Odds Ratio (OR)=13 (95% Confidence Interval (CI): 0.94-174). Regarding chemotherapy, we observed an increased OR for both alkylating agents and spindle inhibitors, OR=2.7 (95% CI: 0.5-14). Children treated for a gonadal tumour as a FMN were found to be at a higher risk of melanoma, OR=8.7 (95% CI: 0.9-86). The adjusted OR for the local radiation dose was 1.07 (95% CI: 1.00-1.15). In conclusion, radiotherapy may contribute to an increased risk of melanoma as a SMN, but only at very high doses of low linear energy transfer radiation. Common genetic origins between gonadal tumours and malignant melanomas are likely.

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