Structural Characterization of the Molten Globule and Native States of Apomyoglobin by Solution X-ray Scattering

Kataoka, Mikio; Nishii, Ichiro; Fujisawa, Tetsuro; Ueki, Tatzuo; Tokunaga, Fumio; Goto, Yuji

doi:10.1006/jmbi.1995.0290

Cited by 221 publications

(240 citation statements)

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“…These values correspond well to the mode of the simulated SAXS ensemble under native-like conditions (15.2 Å) and the average R g in 4 M urea (22.3 Å), respectively. The average of R g under native-like conditions (18.8 Å) is in good agreement with the 10%-25% expansion that was observed for molten globules relative to a fully compact state (28). (Fig.…”

Section: Resultssupporting

confidence: 86%

Conformational selection in the molten globule state of the nuclear coactivator binding domain of CBP

Kjærgaard

Teilum

Poulsen

2010

Proc. Natl. Acad. Sci. U.S.A.

153

242

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Native molten globules are the most folded kind of intrinsically disordered proteins. Little is known about the mechanism by which native molten globules bind to their cognate ligands to form fully folded complexes. The nuclear coactivator binding domain (NCBD) of CREB binding protein is particularly interesting in this respect as structural studies of its complexes have shown that NCBD folds into two remarkably different states depending on the ligand being ACTR or IRF-3. The ligand-free state of NCBD was characterized in order to understand the mechanism of folding upon ligand binding. Biophysical studies show that despite the molten globule nature of the domain, it contains a small cooperatively folded core. By NMR spectroscopy, we have demonstrated that the folded core of NCBD has a well ordered conformer with specific side chain packing. This conformer resembles the structure of the NCBD in complex with the protein ligand, ACTR, suggesting that ACTR binds to prefolded NCBD molecules from the ensemble of interconverting structures.CREB binding protein | folding upon binding | NMR spectroscopy T he protein structure-function paradigm has dominated structural and molecular biology over the past five decades. This paradigm has been challenged by the discovery of functional but intrinsically disordered proteins (IDPs) (1). IDPs are abundant in higher organisms and are necessary for many crucial biological functions such as cell cycle regulation, signal transduction, and regulation of transcription (2, 3). Structural studies of IDPs have shown that despite the high degree of disorder, these proteins are far from randomly structured and form transient, yet specific, secondary and tertiary structural elements (4, 5). The success of the structure-function paradigm in explaining the function of folded proteins suggests that the functions of the IDPs may also be understood by studying the transient structure of the disordered state.The molten globule was originally discovered as a partially folded state under mildly denaturing conditions and was shown to accumulate as an intermediate during protein folding reactions (6, 7). With the emergence of the IDPs, proteins were discovered where the molten globule is the functionally active state. Native molten globules are the most compact conformational state considered as IDPs (4). Molten globules have native-like secondary structure, but are believed to lack the well-defined tertiary interactions found in folded proteins. Most high resolution NMR studies of the molten globule state have focused on the secondary structure of the backbone as this is more readily accessible from secondary chemical shifts (8). The degree of side chain packing, however, is less well understood. Molten globules are believed to have dynamic hydrophobic cores due to the lack of signal in the near-UV CD spectrum and the broadening of NMR signals of aromatic groups (6, 7). Recent studies have shown that the side chains in the α-lactalbumin molten globule exchange between several well defined confor...

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Section: Resultssupporting

confidence: 86%

Conformational selection in the molten globule state of the nuclear coactivator binding domain of CBP

Kjærgaard

Teilum

Poulsen

2010

Proc. Natl. Acad. Sci. U.S.A.

153

242

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“…The structural characterization of the compact denatured states is essential and important for the better understanding of the protein folding and stability. Throughout this paper, we will use the term molten globule to describe the compact denatured state of cytochrome c, a-lactalbumin, and apomyoglobin, because these have been regarded as typical molten globules, although we understand that the real structure of the so-called molten globule is different from the original definition (Baum et al, 1989;Hughson et al, 1990;Alexandrescu et al, 1993;Chyan et al, 1993;Kataoka et al, 1995;Loh et al;, Privalov, 1996.…”

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confidence: 99%

Structural characterization of the molten globule of α‐lactalbumin by solution X‐ray scattering

et al. 1997

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A compact denatured state is often observed under a mild denaturation condition for various proteins. A typical example is the a-lactalbumin molten globule. Although the molecular compactness and shape are the essential properties for defining the molten globule, there have been ambiguities of these properties for the molten globule of a-lactalbumin. Using solution X-ray scattering, we have examined the structural properties of two types of molten globule of a-lactalbumin, the apo-protein at neutral pH and the acid molten globule. The radius of gyration for the native holo-protein was 15.7 A, but the two different molten globules both had a radius of gyration of 17.2 A. The maximum dimension of the molecule was also increased from 50 8, for the native state to 60 8, for the molten globule. These values clearly indicate that the molten globule is not as compact as the native state. The increment in the radius of gyration was less than 10% for the a-lactalbumin molten globule, compared with up to 30% for the molten globules of other globular proteins. Intramolecular disulfide bonds restrict the molecular expansion of the molten globule. The distance distribution function of the a-lactalbumin molten globule is composed of a single peak suggesting a globular shape, which is simply swollen from the native state. The scattering profile in the high Q region of the molten globule indicates the presence of a significant amount of tertiary fold. Based on the structural properties obtained by solution X-ray scattering, general and conceptual structural images for the molten globules of various proteins are described and compared with the individual, detailed structural model obtained by nuclear magnetic resonance.

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“…In general, the scattering curve for a globular conformation follows Porod's law, I(q) / q À4 in the large-q region, whereas the scattering profile from an expanded unfolding conformation is proportional to q À2 at moderate q, and is then proportional to q À1 at small q values (Glatter, 1982;Flanagan et al, 1992;Kataoka et al, 1993Kataoka et al, , 1995. Furthermore, the Kratky plot of the scattering curve for the globular structure shows a clear peak, whereas that of a molten globule has a plateau and then increases gradually with q (Glatter, 1982;Flanagan et al, 1992;Kataoka et al, 1993Kataoka et al, , 1995.…”

Section: Saxs Analysis Of Rseas and Their Complexes With Rsebmentioning

confidence: 99%

“…Furthermore, the Kratky plot of the scattering curve for the globular structure shows a clear peak, whereas that of a molten globule has a plateau and then increases gradually with q (Glatter, 1982;Flanagan et al, 1992;Kataoka et al, 1993Kataoka et al, , 1995. Thus, Kratky analysis was further carried out for the measured SAXS data in order to obtain more useful information on the folding status.…”

Section: Saxs Analysis Of Rseas and Their Complexes With Rsebmentioning

confidence: 99%

Solution structures of RseA and its complex with RseB

Jin

Kim

Rho

et al. 2008

J Synchrotron Radiat

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The bacterial envelope stress response, which is responsible for sensing stress signals in the envelope and for turning on the E -dependent transcription, is modulated by the binding of RseB to RseA. In this study, the solution structures of RseA and its complex with RseB were analyzed using circular dichroism and small-angle X-ray scattering. The periplasmic domain of RseA is unstructured and flexible when it is not bound to RseB. However, upon the formation of the stable complex with RseB, RseA induces conformational changes in RseB and, at the same time, RseA becomes more structured. Furthermore, it appears that some other undefined region of RseA, as well as the previously identified minimum region (amino acid 169-186), is also involved in RseB binding. It is thought that these conformational changes are relevant to the proteolytic cleavage of RseA and the modulation of envelope stress response.

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Structural Characterization of the Molten Globule and Native States of Apomyoglobin by Solution X-ray Scattering

Cited by 221 publications

References 0 publications

Conformational selection in the molten globule state of the nuclear coactivator binding domain of CBP

Conformational selection in the molten globule state of the nuclear coactivator binding domain of CBP

Structural characterization of the molten globule of α‐lactalbumin by solution X‐ray scattering

Solution structures of RseA and its complex with RseB

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