BEGIN:VCALENDAR VERSION:2.0 PRODID:-//jEvents 2.0 for Joomla//EN CALSCALE:GREGORIAN METHOD:PUBLISH BEGIN:VEVENT UID:c98c679c21ff07a760762f3ad238031e CATEGORIES:Seminar CREATED:20171116T191618 SUMMARY:Dr. Jeff Martell LOCATION:WL260 DESCRIPTION:
Tuesday November 28, 2017
Wright-Re iman Room 260 at 11:00 am
"Three-Dimensio nal Scaffold Engineering: Enzyme Active Sites and Nanoporous Mate rials"
I will present my work on molecular engineering of three-dimen sional scaffolds—specifically, enzyme active sites and pores of metal– organic frameworks (MOFs)—for biological and environmental application s. In the first part, I will describe the development of heme peroxida se enzymes as genetically encoded probes for cell biology. Fluorescent proteins such as GFP have been revolutionary in allowing specific pro teins to be tracked within living cells, but the resolution of fluorescence microscopy (~200 nm) is often inadequate for determining precise subc ellular localization. Electron microscopy (EM), on the other hand, offers far superior resolution (developed for EM. Using rational enzyme engineering and directed evolution, we develo ped APEX (enhanced ascorbate peroxidase), a heme peroxidase that funct ions as a versatile genetic tag for electron microscopy and several ot her applications in cell biology. In the second part, I will present t he concept of engineering nanopores within MOFs to mimic protein activ e sites, thus enabling capture of specific guest molecules in a robust and recyclable material. I will demonstrate this concept for two examples: capture of carbon dioxide (CO2) and enantioselective recognition. I w ill first present a class of diamine-appended MOFs that capture CO2 by an u nprecedented cooperative mechanism. Through systematic variation of th e diamine and framework structures, we established a fundamental struc ture–property relationship and improved the long-term stability and re usability of these materials. I will also describe the development of a chi ral MOF with a large pore diameter, permanent porosity, and high stabi lity—attributes that make it promising for separation of chiral pharma ceuticals. I will show that this framework exhibits high enantioselectivity in the formation of ammonium carbamates within its pores. By combinin g numerous techniques in X-ray diffraction and solid-state spectroscop y, we elucidated the mechanism of enantioselectivity, which involves an ext ensive network of hydrogen bonds and van der Waals interactions b etween the three-dimensional framework scaffold and the ammonium carbamate guest molecules.
~Coffee/tea will be served prior to lect ure~
X-ALT-DESC;FMTTYPE=text/html:Tuesday November 28, 2017
Wright-Reiman Room 260 at 11:00 am
"Three-Dimensional Scaffold Engineering: Enzyme Active Si tes and Nanoporous Materials"
I will present my work on molecula r engineering of three-dimensional scaffolds—specifically, enzyme acti ve sites and pores of metal–organic frameworks (MOFs)—for biological and en vironmental applications. In the first part, I will describe the development of heme peroxidase enzymes as genetically encoded probes f or cell biology. Fluorescent proteins such as GFP have been revolutionary i n allowing specific proteins to be tracked within living cells, but th e resolution of fluorescence microscopy (~200 nm) is often inadequate for determining precise subcellular localization. Electron microscopy (EM), on the&nbs p;other hand, offers far superior resolution (developed for EM. Using ratio nal enzyme engineering and directed evolution, we developed APEX (enha nced ascorbate peroxidase), a heme peroxidase that functions as a versatile genetic tag for electron microscopy and several other applications in cell biology. In the second part, I will present the concept of engin eering nanopores within MOFs to mimic protein active sites, thus enabl ing capture of specific guest molecules in a robust and recyclable material . I will demonstrate this concept for two examples: capture of carbon dioxide (CO2) and enantioselective recognition. I will first present a class of diamine-appended MOFs that capture CO2 by an unprecedented c ooperative mechanism. Through systematic variation of the diamine and frame work structures, we established a fundamental structure–property relat ionship and improved the long-term stability and reusability of these materials. I will also describe the development of a chiral MOF with a larg e pore diameter, permanent porosity, and high stability—attributes tha t make it promising for separation of chiral pharmaceuticals. I will s how that this framework exhibits high enantioselectivity in the formation&n bsp;of ammonium carbamates within its pores. By combining numerous techniqu es in X-ray diffraction and solid-state spectroscopy, we elucidated th e mechanism of enantioselectivity, which involves an extensive network of hydrogen bonds and van der Waals interactions between the three-di mensional framework scaffold and the ammonium carbamate guest molecules.
~Coffee/tea will be served prior to lecture~< /p> DTSTAMP:20240329T115458 DTSTART:20171128T160000 DTEND:20171128T170000 SEQUENCE:0 TRANSP:OPAQUE END:VEVENT END:VCALENDAR