Graceffa, Rita

[["dc.bibliographiccitation.firstpage","10562"],["dc.bibliographiccitation.issue","29"],["dc.bibliographiccitation.journal","PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA"],["dc.bibliographiccitation.lastpage","10567"],["dc.bibliographiccitation.volume","111"],["dc.contributor.author","Nobrega, R. Paul"],["dc.contributor.author","Arora, Karunesh"],["dc.contributor.author","Kathuria, Sagar V."],["dc.contributor.author","Graceffa, Rita"],["dc.contributor.author","Barrea, Raul A."],["dc.contributor.author","Guo, Liang"],["dc.contributor.author","Chakravarthy, Srinivas"],["dc.contributor.author","Bilsel, Osman"],["dc.contributor.author","Irving, Thomas C."],["dc.contributor.author","Brooks, Charles L., III"],["dc.contributor.author","Matthews, C. Robert"],["dc.date.accessioned","2018-11-07T09:37:35Z"],["dc.date.available","2018-11-07T09:37:35Z"],["dc.date.issued","2014"],["dc.description.abstract","Folding of globular proteins can be envisioned as the contraction of a random coil unfolded state toward the native state on an energy surface rough with local minima trapping frustrated species. These substructures impede productive folding and can serve as nucleation sites for aggregation reactions. However, little is known about the relationship between frustration and its underlying sequence determinants. Chemotaxis response regulator Y (CheY), a 129-amino acid bacterial protein, has been shown previously to populate an off-pathway kinetic trap in the microsecond time range. The frustration has been ascribed to premature docking of the N- and C-terminal subdomains or, alternatively, to the formation of an unproductive local-in-sequence cluster of branched aliphatic side chains, isoleucine, leucine, and valine (ILV). The roles of the subdomains and ILV clusters in frustration were tested by altering the sequence connectivity using circular permutations. Surprisingly, the stability and buried surface area of the intermediate could be increased or decreased depending on the location of the termini. Comparison with the results of small-angle X-ray-scattering experiments and simulations points to the accelerated formation of a more compact, on-pathway species for the more stable intermediate. The effect of chain connectivity in modulating the structures and stabilities of the early kinetic traps in CheY is better understood in terms of the ILV cluster model. However, the subdomain model captures the requirement for an intact N-terminal domain to access the native conformation. Chain entropy and aliphatic-rich sequences play crucial roles in biasing the early events leading to frustration in the folding of CheY."],["dc.identifier.doi","10.1073/pnas.1324230111"],["dc.identifier.isi","000339310700046"],["dc.identifier.pmid","25002512"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/32871"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","0027-8424"],["dc.title","Modulation of frustration in folding by sequence permutation"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","4281"],["dc.bibliographiccitation.issue","9"],["dc.bibliographiccitation.journal","Journal of Mechanical Science and Technology"],["dc.bibliographiccitation.lastpage","4289"],["dc.bibliographiccitation.volume","33"],["dc.contributor.author","Inguva, Venkatesh"],["dc.contributor.author","Graceffa, Rita"],["dc.contributor.author","Schulz-Schaeffer, Walter Joachim"],["dc.contributor.author","Bilsel, Osman"],["dc.contributor.author","Perot, Blair J."],["dc.date.accessioned","2020-03-03T08:11:21Z"],["dc.date.available","2020-03-03T08:11:21Z"],["dc.date.issued","2019"],["dc.description.abstract","A focused jet is an axisymmetric jet of liquid surrounded by an outer coaxial gas jet. The gas jet is typically used to compress the liquid jet in the radial direction thereby focusing it. At microscales, it is difficult to manufacture micro-scale delivery nozzles (needles) and to consistently align and axially position the liquid and the gas needles. However, it is very easy, using standard etching technologies to make precise and repeatable rectangular nozzle designs. This work will therefore explore the geometric and fluid dynamics constraints that allow one to design rectangular nozzles that produce round coaxial micro-jets of liquid and gas. Because of the small scales, the fluid dynamics of the focusing jet is unusual, and this work demonstrates that the liquid jet is best focused by shear stretching and not via gas compression. This paper shows that sheet jetting occurs when the Reynolds number of the gas is too high. Dripping occurs when the Weber number of the liquid is too low. The desired round jet occurs by balancing Weber number of the liquid jet and Reynolds number of the gas such that surface tension at the interface holds the water jet round while the acceleration of the water jet due to shear at the interface from fast-moving air causes the liquid jet cross-sectional area to decrease. The goal of this initial paper is to demonstrate that a parameter region exists where this flow behavior is possible."],["dc.identifier.doi","10.1007/s12206-019-0824-x"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/63065"],["dc.language.iso","en"],["dc.relation.issn","1738-494X"],["dc.relation.issn","1976-3824"],["dc.title","Creating round focused micro-jets from rectangular nozzles"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","820"],["dc.bibliographiccitation.journal","Journal of Synchrotron Radiation"],["dc.bibliographiccitation.lastpage","825"],["dc.bibliographiccitation.volume","20"],["dc.contributor.author","Graceffa, Rita"],["dc.contributor.author","Nobrega, R. Paul"],["dc.contributor.author","Barrea, Raul A."],["dc.contributor.author","Kathuria, Sagar V."],["dc.contributor.author","Chakravarthy, Srinivas"],["dc.contributor.author","Bilsel, Osman"],["dc.contributor.author","Irving, Thomas C."],["dc.date.accessioned","2018-11-07T09:18:19Z"],["dc.date.available","2018-11-07T09:18:19Z"],["dc.date.issued","2013"],["dc.description.abstract","Small-angle X-ray scattering (SAXS) is a well established technique to probe the nanoscale structure and interactions in soft matter. It allows one to study the structure of native particles in near physiological environments and to analyze structural changes in response to variations in external conditions. The combination of microfluidics and SAXS provides a powerful tool to investigate dynamic processes on a molecular level with sub-millisecond time resolution. Reaction kinetics in the sub-millisecond time range has been achieved using continuous-flow mixers manufactured using micromachining techniques. The time resolution of these devices has previously been limited, in part, by the X-ray beam sizes delivered by typical SAXS beamlines. These limitations can be overcome using optics to focus X-rays to the micrometer size range providing that beam divergence and photon flux suitable for performing SAXS experiments can be maintained. Such micro-SAXS in combination with microfluidic devices would be an attractive probe for time-resolved studies. Here, the development of a high-duty-cycle scanning microsecond-time-resolution SAXS capability, built around the Kirkpatrick-Baez mirror-based microbeam system at the Biophysics Collaborative Access Team (BioCAT) beamline 18ID at the Advanced Photon Source, Argonne National Laboratory, is reported. A detailed description of the microbeam small-angle-scattering instrument, the turbulent flow mixer, as well as the data acquisition and control and analysis software is provided. Results are presented where this apparatus was used to study the folding of cytochrome c. Future prospects for this technique are discussed."],["dc.identifier.doi","10.1107/S0909049513021833"],["dc.identifier.isi","000325639200002"],["dc.identifier.pmid","24121320"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/28382"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","1600-5775"],["dc.relation.issn","0909-0495"],["dc.title","Sub-millisecond time-resolved SAXS using a continuous-flow mixer and X-ray microbeam"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]