Matching Items (12)
Description
Nanolasers represents the research frontier in both the areas of photonics and nanotechnology for its interesting properties in low dimension physics, its appealing prospects in integrated photonics, and other on-chip applications. In this thesis, I present my research work on fabrication and characterization of a new type of nanolasers: metallic cavity nanolasers. The last ten years witnessed a dramatic paradigm shift from pure dielectric cavity to metallic cavity in the research of nanolasers. By using low loss metals such as silver, which is highly reflective at near infrared, light can be confined in an ultra small cavity or waveguide with sub-wavelength dimensions, thus enabling sub-wavelength cavity lasers. Based on this idea, I fabricated two different kinds of metallic cavity nanolasers with rectangular and circular geometries with InGaAs as the gain material and silver as the metallic shell. The lasing wavelength is around 1.55 μm, intended for optical communication applications. Continuous wave (CW) lasing at cryogenic temperature under current injection was achieved on devices with a deep sub-wavelength physical cavity volume smaller than 0.2 λ3. Improving device fabrication process is one of the main challenges in the development of metallic cavity nanolasers due to its ultra-small size. With improved fabrication process and device design, CW lasing at room temperature was demonstrated as well on a sub-wavelength rectangular device with a physical cavity volume of 0.67 λ3. Experiments verified that a small circular nanolasers supporting TE¬01 mode can generate an azimuthal polarized laser beam, providing a compact such source under electrical injection. Sources with such polarizations could have many special applications. Study of digital modulation of circular nanolasers showed that laser noise is an important factor that will affect the data rate of the nanolaser when used as the light source in optical interconnects. For future development, improving device fabrication processes is required to improve device performance. In addition, techniques need to be developed to realize nanolaser/Si waveguide integration. In essence, resolving these two critical issues will finally pave the way for these nanolasers to be used in various practical applications.
ContributorsDing, Kang (Author) / Ning, Cun-Zheng (Thesis advisor) / Yu, Hongbin (Committee member) / Palais, Joseph (Committee member) / Zhang, Yong-Hang (Committee member) / Arizona State University (Publisher)
Created2014
Description
Crystal structure determination of biological macromolecules using the novel technique of serial femtosecond crystallography (SFX) is severely limited by the scarcity of X-ray free-electron laser (XFEL) sources. However, recent and future upgrades render microfocus beamlines at synchrotron-radiation sources suitable for room-temperature serial crystallography data collection also. Owing to the longer exposure times that are needed at synchrotrons, serial data collection is termed serial millisecond crystallography (SMX). As a result, the number of SMX experiments is growing rapidly, with a dozen experiments reported so far. Here, the first high-viscosity injector-based SMX experiments carried out at a US synchrotron source, the Advanced Photon Source (APS), are reported. Microcrystals (5–20 µm) of a wide variety of proteins, including lysozyme, thaumatin, phycocyanin, the human A[subscript 2A] adenosine receptor (A[subscript 2A]AR), the soluble fragment of the membrane lipoprotein Flpp3 and proteinase K, were screened. Crystals suspended in lipidic cubic phase (LCP) or a high-molecular-weight poly(ethylene oxide) (PEO; molecular weight 8 000 000) were delivered to the beam using a high-viscosity injector. In-house data-reduction (hit-finding) software developed at APS as well as the SFX data-reduction and analysis software suites Cheetah and CrystFEL enabled efficient on-site SMX data monitoring, reduction and processing. Complete data sets were collected for A[subscript 2A]AR, phycocyanin, Flpp3, proteinase K and lysozyme, and the structures of A[subscript 2A]AR, phycocyanin, proteinase K and lysozyme were determined at 3.2, 3.1, 2.65 and 2.05 Å resolution, respectively. The data demonstrate the feasibility of serial millisecond crystallography from 5–20 µm crystals using a high-viscosity injector at APS. The resolution of the crystal structures obtained in this study was dictated by the current flux density and crystal size, but upcoming developments in beamline optics and the planned APS-U upgrade will increase the intensity by two orders of magnitude. These developments will enable structure determination from smaller and/or weakly diffracting microcrystals.
ContributorsMartin Garcia, Jose Manuel (Author) / Conrad, Chelsie (Author) / Nelson, Garrett (Author) / Stander, Natasha (Author) / Zatsepin, Nadia (Author) / Zook, James (Author) / Zhu, Lan (Author) / Geiger, James (Author) / Chun, Eugene (Author) / Kissick, David (Author) / Hilgart, Mark C. (Author) / Ogata, Craig (Author) / Ishchenko, Andrii (Author) / Nagaratnam, Nirupa (Author) / Roy Chowdhury, Shatabdi (Author) / Coe, Jesse (Author) / Subramanian, Ganesh (Author) / Schaffer, Alexander (Author) / James, Daniel (Author) / Ketwala, Gihan (Author) / Venugopalan, Nagarajan (Author) / Xu, Shenglan (Author) / Corcoran, Stephen (Author) / Ferguson, Dale (Author) / Weierstall, Uwe (Author) / Spence, John (Author) / Cherezov, Vadim (Author) / Fromme, Petra (Author) / Fischetti, Robert F. (Author) / Liu, Wei (Author) / College of Liberal Arts and Sciences (Contributor) / School of Molecular Sciences (Contributor) / Biodesign Institute (Contributor) / Applied Structural Discovery (Contributor) / Department of Physics (Contributor)
Created2017-05-24
Description
Diacylglycerol kinase catalyses the ATP-dependent conversion of diacylglycerol to phosphatidic acid in the plasma membrane of Escherichia coli. The small size of this integral membrane trimer, which has 121 residues per subunit, means that available protein must be used economically to craft three catalytic and substrate-binding sites centred about the membrane/cytosol interface. How nature has accomplished this extraordinary feat is revealed here in a crystal structure of the kinase captured as a ternary complex with bound lipid substrate and an ATP analogue. Residues, identified as essential for activity by mutagenesis, decorate the active site and are rationalized by the ternary structure. The γ-phosphate of the ATP analogue is positioned for direct transfer to the primary hydroxyl of the lipid whose acyl chain is in the membrane. A catalytic mechanism for this unique enzyme is proposed. The active site architecture shows clear evidence of having arisen by convergent evolution.
ContributorsLi, Dianfan (Author) / Stansfeld, Phillip J. (Author) / Sansom, Mark S. P. (Author) / Keogh, Aaron (Author) / Vogeley, Lutz (Author) / Howe, Nicole (Author) / Lyons, Joseph A. (Author) / Aragao, David (Author) / Fromme, Petra (Author) / Fromme, Raimund (Author) / Basu, Shibom (Author) / Grotjohann, Ingo (Author) / Kupitz, Christopher (Author) / Rendek, Kimberley (Author) / Weierstall, Uwe (Author) / Zatsepin, Nadia (Author) / Cherezov, Vadim (Author) / Liu, Wei (Author) / Bandaru, Sateesh (Author) / English, Niall J. (Author) / Gati, Cornelius (Author) / Barty, Anton (Author) / Yefanov, Oleksandr (Author) / Chapman, Henry N. (Author) / Diederichs, Kay (Author) / Messerschmidt, Marc (Author) / Boutet, Sebastien (Author) / Williams, Garth J. (Author) / Seibert, M. Marvin (Author) / Caffrey, Martin (Author) / College of Liberal Arts and Sciences (Contributor) / School of Molecular Sciences (Contributor) / Biodesign Institute (Contributor) / Applied Structural Discovery (Contributor) / Department of Physics (Contributor)
Created2015-12-17
Description
Serial femtosecond X-ray crystallography (SFX) using an X-ray free electron laser (XFEL) is a recent advancement in structural biology for solving crystal structures of challenging membrane proteins, including G-protein coupled receptors (GPCRs), which often only produce microcrystals. An XFEL delivers highly intense X-ray pulses of femtosecond duration short enough to enable the collection of single diffraction images before significant radiation damage to crystals sets in. Here we report the deposition of the XFEL data and provide further details on crystallization, XFEL data collection and analysis, structure determination, and the validation of the structural model. The rhodopsin-arrestin crystal structure solved with SFX represents the first near-atomic resolution structure of a GPCR-arrestin complex, provides structural insights into understanding of arrestin-mediated GPCR signaling, and demonstrates the great potential of this SFX-XFEL technology for accelerating crystal structure determination of challenging proteins and protein complexes.
ContributorsZhou, X. Edward (Author) / Gao, Xiang (Author) / Barty, Anton (Author) / Kang, Yanyong (Author) / He, Yuanzheng (Author) / Liu, Wei (Author) / Ishchenko, Andrii (Author) / White, Thomas A. (Author) / Yefanov, Oleksandr (Author) / Han, Gye Won (Author) / Xu, Qingping (Author) / de Waal, Parker W. (Author) / Suino-Powell, Kelly M. (Author) / Boutet, Sebastien (Author) / Williams, Garth J. (Author) / Wang, Meitian (Author) / Li, Dianfan (Author) / Caffrey, Martin (Author) / Chapman, Henry N. (Author) / Spence, John (Author) / Fromme, Petra (Author) / Weierstall, Uwe (Author) / Stevens, Raymond C. (Author) / Cherezov, Vadim (Author) / Melcher, Karsten (Author) / Xu, H. Eric (Author) / College of Liberal Arts and Sciences (Contributor) / School of Molecular Sciences (Contributor) / Biodesign Institute (Contributor) / Applied Structural Discovery (Contributor) / Department of Physics (Contributor)
Created2016-04-12
Description
Lipidic cubic phases (LCPs) have emerged as successful matrixes for the crystallization of membrane proteins. Moreover, the viscous LCP also provides a highly effective delivery medium for serial femtosecond crystallography (SFX) at X-ray free-electron lasers (XFELs). Here, the adaptation of this technology to perform serial millisecond crystallography (SMX) at more widely available synchrotron microfocus beamlines is described. Compared with conventional microcrystallography, LCP-SMX eliminates the need for difficult handling of individual crystals and allows for data collection at room temperature. The technology is demonstrated by solving a structure of the light-driven proton-pump bacteriorhodopsin (bR) at a resolution of 2.4 Å. The room-temperature structure of bR is very similar to previous cryogenic structures but shows small yet distinct differences in the retinal ligand and proton-transfer pathway.
ContributorsNogly, Przemyslaw (Author) / James, Daniel (Author) / Wang, Dingjie (Author) / White, Thomas A. (Author) / Zatsepin, Nadia (Author) / Shilova, Anastasya (Author) / Nelson, Garrett (Author) / Liu, Haiguang (Author) / Johansson, Linda (Author) / Heymann, Michael (Author) / Jaeger, Kathrin (Author) / Metz, Markus (Author) / Wickstrand, Cecilia (Author) / Wu, Wenting (Author) / Bath, Petra (Author) / Berntsen, Peter (Author) / Oberthuer, Dominik (Author) / Panneels, Valerie (Author) / Cherezov, Vadim (Author) / Chapman, Henry (Author) / Schertler, Gebhard (Author) / Neutze, Richard (Author) / Spence, John (Author) / Moraes, Isabel (Author) / Burghammer, Manfred (Author) / Standfuss, Joerg (Author) / Weierstall, Uwe (Author) / College of Liberal Arts and Sciences (Contributor) / Department of Physics (Contributor)
Created2015-01-27
Description
Serial femtosecond crystallography (SFX) has opened a new era in crystallography by permitting nearly damage-free, room-temperature structure determination of challenging proteins such as membrane proteins. In SFX, femtosecond X-ray free-electron laser pulses produce diffraction snapshots from nanocrystals and microcrystals delivered in a liquid jet, which leads to high protein consumption. A slow-moving stream of agarose has been developed as a new crystal delivery medium for SFX. It has low background scattering, is compatible with both soluble and membrane proteins, and can deliver the protein crystals at a wide range of temperatures down to 4°C. Using this crystal-laden agarose stream, the structure of a multi-subunit complex, phycocyanin, was solved to 2.5 Å resolution using 300 µg of microcrystals embedded into the agarose medium post-crystallization. The agarose delivery method reduces protein consumption by at least 100-fold and has the potential to be used for a diverse population of proteins, including membrane protein complexes.
ContributorsConrad, Chelsie (Author) / Basu, Shibom (Author) / James, Daniel (Author) / Wang, Dingjie (Author) / Schaffer, Alexander (Author) / Roy Chowdhury, Shatabdi (Author) / Zatsepin, Nadia (Author) / Aquila, Andrew (Author) / Coe, Jesse (Author) / Gati, Cornelius (Author) / Hunter, Mark S. (Author) / Koglin, Jason E. (Author) / Kupitz, Christopher (Author) / Nelson, Garrett (Author) / Subramanian, Ganesh (Author) / White, Thomas A. (Author) / Zhao, Yun (Author) / Zook, James (Author) / Boutet, Sebastien (Author) / Cherezov, Vadim (Author) / Spence, John (Author) / Fromme, Raimund (Author) / Weierstall, Uwe (Author) / Fromme, Petra (Author) / Department of Chemistry and Biochemistry (Contributor) / Biodesign Institute (Contributor) / Applied Structural Discovery (Contributor) / College of Liberal Arts and Sciences (Contributor) / Department of Physics (Contributor) / School of Molecular Sciences (Contributor)
Created2015-06-30
Description
Serial femtosecond crystallography (SFX) at X-ray free-electron lasers (XFELs) enables high-resolution protein structure determination using micrometre-sized crystals at room temperature with minimal effects from radiation damage. SFX requires a steady supply of microcrystals intersecting the XFEL beam at random orientations. An LCP–SFX method has recently been introduced in which microcrystals of membrane proteins are grown and delivered for SFX data collection inside a gel-like membrane-mimetic matrix, known as lipidic cubic phase (LCP), using a special LCP microextrusion injector. Here, it is demonstrated that LCP can also be used as a suitable carrier medium for microcrystals of soluble proteins, enabling a dramatic reduction in the amount of crystallized protein required for data collection compared with crystals delivered by liquid injectors. High-quality LCP–SFX data sets were collected for two soluble proteins, lysozyme and phycocyanin, using less than 0.1 mg of each protein.
ContributorsFromme, Raimund (Author) / Ishchenko, Andrii (Author) / Metz, Markus (Author) / Roy Chowdhury, Shatabdi (Author) / Basu, Shibom (Author) / Boutet, Sebastien (Author) / Fromme, Petra (Author) / White, Thomas A. (Author) / Barty, Anton (Author) / Spence, John (Author) / Weierstall, Uwe (Author) / Liu, Wei (Author) / Cherezov, Vadim (Author) / Biodesign Institute (Contributor) / Applied Structural Discovery (Contributor) / College of Liberal Arts and Sciences (Contributor) / Department of Physics (Contributor)
Created2015-08-04
Description
Serial femtosecond crystallography (SFX) using X-ray free-electron lasers has produced high-resolution, room temperature, time-resolved protein structures. We report preliminary SFX of Sindbis virus, an enveloped icosahedral RNA virus with ∼700 Å diameter. Microcrystals delivered in viscous agarose medium diffracted to ∼40 Å resolution. Small-angle diffuse X-ray scattering overlaid Bragg peaks and analysis suggests this results from molecular transforms of individual particles. Viral proteins undergo structural changes during entry and infection, which could, in principle, be studied with SFX. This is an important step toward determining room temperature structures from virus microcrystals that may enable time-resolved studies of enveloped viruses.
ContributorsLawrence, Robert (Author) / Conrad, Chelsie (Author) / Zatsepin, Nadia (Author) / Grant, Thomas D. (Author) / Liu, Haiguang (Author) / James, Daniel (Author) / Nelson, Garrett (Author) / Subramanian, Ganesh (Author) / Aquila, Andrew (Author) / Hunter, Mark S. (Author) / Liang, Mengning (Author) / Boutet, Sebastien (Author) / Coe, Jesse (Author) / Spence, John (Author) / Weierstall, Uwe (Author) / Liu, Wei (Author) / Fromme, Petra (Author) / Cherezov, Vadim (Author) / Hogue, Brenda (Author) / Biodesign Institute (Contributor) / Infectious Diseases and Vaccinology (Contributor) / Applied Structural Discovery (Contributor) / Department of Chemistry and Biochemistry (Contributor) / College of Liberal Arts and Sciences (Contributor) / Department of Physics (Contributor) / School of Life Sciences (Contributor)
Created2015-08-20
Description
Serial femtosecond crystallography (SFX) takes advantage of extremely bright and ultrashort pulses produced by x-ray free-electron lasers (XFELs), allowing for the collection of high-resolution diffraction intensities from micrometer-sized crystals at room temperature with minimal radiation damage, using the principle of “diffraction-before-destruction.” However, de novo structure factor phase determination using XFELs has been difficult so far. We demonstrate the ability to solve the crystallographic phase problem for SFX data collected with an XFEL using the anomalous signal from native sulfur atoms, leading to a bias-free room temperature structure of the human A[subscript 2A] adenosine receptor at 1.9 Å resolution. The advancement was made possible by recent improvements in SFX data analysis and the design of injectors and delivery media for streaming hydrated microcrystals. This general method should accelerate structural studies of novel difficult-to-crystallize macromolecules and their complexes.
ContributorsBatyuk, Alexander (Author) / Galli, Lorenzo (Author) / Ishchenko, Andrii (Author) / Han, Gye Won (Author) / Gati, Cornelius (Author) / Popov, Petr A. (Author) / Lee, Ming-Yue (Author) / Stauch, Benjamin (Author) / White, Thomas A. (Author) / Barty, Anton (Author) / Aquila, Andrew (Author) / Hunter, Mark S. (Author) / Liang, Mengning (Author) / Boutet, Sebastien (Author) / Pu, Mengchen (Author) / Liu, Zhi-jie (Author) / Nelson, Garrett (Author) / James, Daniel (Author) / Li, Chufeng (Author) / Zhao, Yun (Author) / Spence, John (Author) / Liu, Wei (Author) / Fromme, Petra (Author) / Katritch, Vsevolod (Author) / Weierstall, Uwe (Author) / Stevens, Raymond C. (Author) / Cherezov, Vadim (Author) / College of Liberal Arts and Sciences (Contributor) / Department of Physics (Contributor) / Biodesign Institute (Contributor) / Applied Structural Discovery (Contributor) / School of Molecular Sciences (Contributor)
Created2016-09-23
Description
We describe the deposition of four datasets consisting of X-ray diffraction images acquired using serial femtosecond crystallography experiments on microcrystals of human G protein-coupled receptors, grown and delivered in lipidic cubic phase, at the Linac Coherent Light Source. The receptors are: the human serotonin receptor 2B in complex with an agonist ergotamine, the human δ-opioid receptor in complex with a bi-functional peptide ligand DIPP-NH2, the human smoothened receptor in complex with an antagonist cyclopamine, and finally the human angiotensin II type 1 receptor in complex with the selective antagonist ZD7155. All four datasets have been deposited, with minimal processing, in an HDF5-based file format, which can be used directly for crystallographic processing with CrystFEL or other software. We have provided processing scripts and supporting files for recent versions of CrystFEL, which can be used to validate the data.
ContributorsWhite, Thomas A. (Author) / Barty, Anton (Author) / Liu, Wei (Author) / Ishchenko, Andrii (Author) / Zhang, Haitao (Author) / Gati, Cornelius (Author) / Zatsepin, Nadia (Author) / Basu, Shibom (Author) / Oberthur, Dominik (Author) / Metz, Markus (Author) / Beyerlein, Kenneth R. (Author) / Yoon, Chun Hong (Author) / Yefanov, Oleksandr M. (Author) / James, Daniel (Author) / Wang, Dingjie (Author) / Messerschmidt, Marc (Author) / Koglin, Jason E. (Author) / Boutet, Sebastien (Author) / Weierstall, Uwe (Author) / Cherezov, Vadim (Author) / College of Liberal Arts and Sciences (Contributor)
Created2016-08-01