Abstract
Cholinesterase-like adhesion molecules (CLAMs) are a family of neuronal cell adhesion molecules with important roles in synaptogenesis, and in maintaining structural and functional integrity of the nervous system. Our earlier study on the cytoplasmic domain of one of these CLAMs, the Drosophila protein, gliotactin, showed that it is intrinsically unstructured in vitro. Bioinformatic analysis suggested that the cytoplasmic domains of other CLAMs are also intrinsically unstructured, even though they bear no sequence homology to each other or to any known protein. In this study, we overexpress and purify the cytoplasmic domain of human neuroligin 3, notwithstanding its high sensitivity to the Escherichia coli endogenous proteases that cause its rapid degradation. Using bioinformatic analysis, sensitivity to proteases, size exclusion chromatography, fluorescence correlation spectroscopy, analytical ultracentrifugation, small angle x-ray scattering, circular dichroism, electron spin resonance, and nuclear magnetic resonance, we show that the cytoplasmic domain of human neuroligin 3 is intrinsically unstructured. However, several of these techniques indicate that it is not fully extended, but becomes significantly more extended under denaturing conditions.
Original language | English |
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Pages (from-to) | 1928-1944 |
Number of pages | 17 |
Journal | Biophysical Journal |
Volume | 95 |
Issue number | 4 |
DOIs | |
State | Published - 15 Aug 2008 |
Externally published | Yes |
Bibliographical note
Funding Information:This research was supported by the Israel Science Foundation; Autism Speaks; the European Commission VI th Framework Research and Technological Development Program (grant No. 031220); the US-Israel Binational Science Foundation (grant No. 2002371); a grant of the Israel Ministry of Science, Culture, and Sport to the Israel Structural Proteomics Center; the Benziyo Center for Neuroscience; the Kimmelman Center for Biomolecular Structure and Assembly; the Minerva Foundation; the Divadol Foundation; the Bruce Rosen Foundation; the Jean and Julia Goldwurm Memorial Foundation; the Neuman Foundation; and by the historic generosity of the Harold Perlman Family. M.L. was supported by Training and Mobility of Research grant No. HPRN-CT-2002-00241 of the European Community. F.A.A.M. is a recipient of a VIDI Scheme grant from the Netherlands Organization for Scientific Research. J.L.S. is the Morton and Gladys Pickman Professor of Structural Biology.