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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Probing conformational changes in orphan nuclear receptor: The NGFI-B intermediate is a partially unfolded dimer

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Garcia, Wanius [1] ; Figueira, Ana Carolina M. [1] ; Neto, Mario de Oliveira [1] ; de Guzzi, Carolina A. [1] ; Buzza, Hilde H. [1] ; Portugal, Rodrigo V. [1] ; Calgaro, Marcos R. [1] ; Polikarpov, Igor [1]
Total Authors: 8
[1] Univ Sao Paulo, Inst Fis Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil
Total Affiliations: 1
Document type: Journal article
Source: Biophysical Chemistry; v. 137, n. 2-3, p. 81-87, OCT 2008.
Web of Science Citations: 1

Human nerve growth factor-induced B (NGFI-B) is a member of the NR4A subfamily of orphan nuclear receptors (NRs). Lacking identified ligands, orphan NRs show particular co-regulator proteins binding properties, different from other NRs, and they might have a non-classical quaternary organization. A body of evidence suggests that NRs recognition of and binding to ligands, DNA, homo- and heterodimerization partners and co-regulator proteins involve significant conformational changes of the NR ligand-binding domains (LBDs). To shed light on largely unknown biophysical properties of NGFI-B, here we studied structural organization and unfolding properties of NGFI-B ligand (like)-binding domain induced by chemical perturbation. Our results show that NGFI-B LBD undergoes a two-state guanidine hydrochloride (GndHCl) induced denaturation, as judged by changes in the a-helical content of the protein monitored by circular dichroism spectroscopy (CD). In contrast, changes in the tertiary structure of NGFI-B LBD, reported by intrinsic fluorescence, reveal a clear intermediate state. Additionally, SAXS results demonstrate that the intermediate observed by intrinsic fluorescence is a partially folded homodimeric structure, which further unfolds without dissociation at higher GndHCl concentrations. This partially unfolded dimeric assembly of NGFI-B LBD might resemble an intermediate that this domain access momentarily in the native state upon interactions with functional partners. (C) 2008 Elsevier B.V. All rights reserved. (AU)

FAPESP's process: 06/00182-8 - Structural biophysics of nuclear receptors and related proteins
Grantee:Igor Polikarpov
Support type: Research Projects - Thematic Grants