Physical Sciences and Mathematics Commons^™

Bidentate Ferrocenyl-Dithiol Reagents For Nanocluster Surface Functionalization, Yiyi Liu

Electronic Thesis and Dissertation Repository

Previous work using monodentate ferrocenyl-chalcogen reagents for nanocluster surface functionalization has indicated an effective way to involve ferrocene moieties onto the surface of these frameworks. However, the abilities of the large polynuclear nanocluster with ferrocene rich surface to form crystalline materials suitable for single crystal X-ray analysis proved to be limited. New bidentate ferrocenyl-chalcogen reagents have been synthesized and characterized in order to probe their ability in this case.

The preparation of new bidentate ferrocenyl chalcogen reagents 1,1’-fc(C{O}OCH₂CH₂SH)₂ (fc = ferrocenyl) and 1,1’-fc(C{O}NHCH₂CH₂SH)₂ are presented. Furthermore, the preparation of silylated …

Structural Basis For Catalysis By The Mono- And Dimetalated Forms Of The Dape-Encoded N-Succinyl-L,L-Diaminopimelic Acid Desuccinylase, Boguslaw Nocek, Danuta Gillner, Yao Fan, Richard Holz, Andzrej Joachimiak

Richard C. Holz

Biosynthesis of lysine and meso-diaminopimelic acid in bacteria provides essential components for protein synthesis and construction of the bacterial peptidoglycan cell wall. The dapE operon enzymes synthesize both meso-diaminopimelic acid and lysine and, therefore, represent potential targets for novel antibacterials. The dapE-encoded N-succinyl-l,l-diaminopimelic acid desuccinylase functions in a late step of the pathway and converts N-succinyl-l,l-diaminopimelic acid to l,l-diaminopimelic acid and succinate. Deletion of the dapE gene is lethal to Helicobacter pylori and Mycobacterium smegmatis, indicating that DapE's are essential for cell growth and proliferation. Since there are no similar pathways in humans, inhibitors …

Lysine Biosynthesis In Bacteria: A Metallodesuccinylase As A Potential Antimicrobial Target, Danuta Gillner, Daniel P. Becker, Richard C. Holz

Richard C. Holz

In this review, we summarize the recent literature on dapE-encoded N-succinyl-l,l-diaminopimelic acid desuccinylase (DapE) enzymes, with an emphasis on structure–function studies that provide insight into the catalytic mechanism. Crystallographic data have also provided insight into residues that might be involved in substrate and hence inhibitor recognition and binding. These data have led to the design and synthesis of several new DapE inhibitors, which are described along with what is known about how inhibitors interact with the active site of DapE enzymes, including the efficacy of a moderately strong DapE inhibitor.

The Fe-Type Nitrile Hydratase From Comamonas Testosteroni Ni1 Does Not Require An Activator Accessory Protein For Expression In Escherichia Coli, Misty Kuhn, Salette Martinez, Natalie Gumataotao, Uwe Bornscheuer, Dali Liu, Richard Holz

Richard C. Holz

We report herein the functional expression of an Fe-type nitrile hydratase (NHase) without the co-expression of an activator protein or the Escherichia coli chaperone proteins GroES/EL. Soluble protein was obtained when the α- and β-subunit genes of the Fe-type NHase Comamonas testosteroni Ni1 (CtNHase) were synthesized with optimized E. coli codon usage and co-expressed. As a control, the Fe-type NHase from Rhodococcus equi TG328–2 (ReNHase) was expressed with (ReNHase+Act) and without (ReNHase−Act) its activator protein, establishing that expression of a fully functional, metallated ReNHase enzyme requires the co-expression of its activator protein, similar to all other Fe-type NHase enzymes reported …

Structure And Function Of Preq1 Riboswitches, Catherine D. Eichhorn, Mijeong Kang, Juli Feigon

Chemistry Department: Faculty Publications

PreQ₁ riboswitches help regulate the biosynthesis and transport of PreQ₁ (7-aminomethyl-7- deazaguanine), a precursor of the hypermodified guanine nucleotide queuosine (Q), in a number of Firmicutes, Proteobacteria, and Fusobacteria. Queuosine is almost universally found at the wobble position of the anticodon in asparaginyl, tyrosyl, histidyl and aspartyl tRNAs, where it contributes to translational fidelity. Two classes of PreQ₁ riboswitches have been identified (PreQ₁-I and PreQ₁-II), and structures of examples from both classes have been determined. Both classes form H-type pseudoknots upon PreQ₁ binding, each of which has distinct unusual features and modes …