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Articles 1 - 6 of 6

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Morphological Transformations In The Magnetite Biomineralizing Protein Mms6 In Iron Solutions: A Small-Angle X‑Ray Scattering Study, Honghu Zhang, Xunpei Liu, Shuren Feng, Wenjie Wang, Klaus Schmidt-Rohr, Mufit Akinc, Marit Nilsen-Hamilton, David Vaknin, Surya K. Mallapragada Feb 2015

Morphological Transformations In The Magnetite Biomineralizing Protein Mms6 In Iron Solutions: A Small-Angle X‑Ray Scattering Study, Honghu Zhang, Xunpei Liu, Shuren Feng, Wenjie Wang, Klaus Schmidt-Rohr, Mufit Akinc, Marit Nilsen-Hamilton, David Vaknin, Surya K. Mallapragada

Chemical and Biological Engineering Publications

Magnetotactic bacteria that produce magnetic nanocrystals of uniform size and well-defined morphologies have inspired the use of biomineralization protein Mms6 to promote formation of uniform magnetic nanocrystals in vitro. Small angle X-ray scattering (SAXS) studies in physiological solutions reveal that Mms6 forms compact globular threedimensional (3D) micelles (approximately 10 nm in diameter) that are, to a large extent, independent of concentration. In the presence of iron ions in the solutions, the general micellar morphology is preserved, however, with associations among micelles that are induced by iron ions. Compared with Mms6, the m2Mms6 mutant (with the sequence of hydroxyl/carboxyl containing ...


Ab Initio Study Of Molecular Interactions In Cellulose Iα, Ajitha Devarajan, Sergiy Markutsya, Monica H. Lamm, Xiaolin Cheng, Jeremy C. Smith, John Ysrael Baluyut, Yana Kholod, Mark S. Gordon, Theresa Lynn Windus Jan 2013

Ab Initio Study Of Molecular Interactions In Cellulose Iα, Ajitha Devarajan, Sergiy Markutsya, Monica H. Lamm, Xiaolin Cheng, Jeremy C. Smith, John Ysrael Baluyut, Yana Kholod, Mark S. Gordon, Theresa Lynn Windus

Chemical and Biological Engineering Publications

Biomass recalcitrance, the resistance of cellulosic biomass to degradation, is due in part to the stability of the hydrogen bond network and stacking forces between the polysaccharide chains in cellulose microfibers. The fragment molecular orbital (FMO) method at the correlated Møller-Plesset second order perturbation level of theory was used on a model of the crystalline cellulose Iα core with a total of 144 glucose units. These computations show that the intersheet chain interactions are stronger than the intrasheet chain interactions for the crystalline structure, while they are more similar to each other for a relaxed structure. An FMO chain ...


Tertiary Structure And Characterization Of A Glycoside Hydrolase Family 44 Endoglucanase From Clostridium Acetobutylicum, Christopher D. Warner, Julie A. Hoy, Taran C. Shilling, Michael J. Linnen, Nathaniel D. Ginder, Clark Ford, Richard B. Honzatko, Peter J. Reilly Jan 2010

Tertiary Structure And Characterization Of A Glycoside Hydrolase Family 44 Endoglucanase From Clostridium Acetobutylicum, Christopher D. Warner, Julie A. Hoy, Taran C. Shilling, Michael J. Linnen, Nathaniel D. Ginder, Clark Ford, Richard B. Honzatko, Peter J. Reilly

Chemical and Biological Engineering Publications

A gene encoding a glycoside hydrolase family 44 (GH44) protein from Clostridium acetobutylicum ATCC 824 was synthesized and transformed into Escherichia coli.The previously uncharacterized protein was expressed with a C-terminal His tag and purified by nickel-nitrilotriacetic acid affinity chromatography. Crystallization and X-ray diffraction to a 2.2-Å resolution revealed a triose phosphate isomerase (TIM) barrel-like structure with additional Greek key and β-sandwich folds, similar to other GH44 crystal structures. The enzyme hydrolyzes cellotetraose and larger cellooligosaccharides, yielding an unbalanced product distribution, including some glucose. It attacks carboxymethylcellulose and xylan at approximately the same rates. Its activity on carboxymethylcellulose is ...


Computational And Experimental Analyses Converge To Reveal A Coherent Yet Malleable Aptamer Structure That Controls Chemical Reactivity, Tianjiao Wang, Julie A. Hoy, Monica H. Lamm, Marit Nilsen-Hamilton Jan 2009

Computational And Experimental Analyses Converge To Reveal A Coherent Yet Malleable Aptamer Structure That Controls Chemical Reactivity, Tianjiao Wang, Julie A. Hoy, Monica H. Lamm, Marit Nilsen-Hamilton

Chemical and Biological Engineering Publications

As short nucleic acids, aptamers in solution are believed to be structurally flexible. Consistent with this view, most aptamers examined for this property have been shown to bind their target molecules by mechanisms that can be described as "induced fit". But, it is not known to what extent this structural flexibility affects the integrity of the target - aptamer interaction. Using the malachite green aptamer (MGA) as a model system, we show that the MGA can protect its bound target, malachite green (MG), from oxidation over several days. Protection is reversed by an oligonucleotide complementary to the MGA binding pocket. Computational ...


Cobalt Ferrite Nanocrystals: Out-Performing Magnetotactic Bacteria, Tanya Prozorov, Pierre E. Palo, Lijun Wang, Marit Nilsen-Hamilton, Deanna Jones, Daniel Orr, Surya K. Mallapragada, Balaji Narasimhan, Paul C. Canfield, Ruslan Prozorov Jan 2007

Cobalt Ferrite Nanocrystals: Out-Performing Magnetotactic Bacteria, Tanya Prozorov, Pierre E. Palo, Lijun Wang, Marit Nilsen-Hamilton, Deanna Jones, Daniel Orr, Surya K. Mallapragada, Balaji Narasimhan, Paul C. Canfield, Ruslan Prozorov

Chemical and Biological Engineering Publications

Magnetotactic bacteria produce exquisitely ordered chains of uniform magnetite (Fe3O4) nanocrystals, and the use of the bacterial mms6 protein allows for the shape-selective synthesis of Fe 3O4 nanocrystals. Cobalt ferrite (CoFe2O 4) nanoparticles, on the other hand, are not known to occur in living organisms. Here we report on the use of the recombinant mms6 protein in a templated synthesis of CoFe2O4 nanocrystals in vitro. We have covalently attached the full-length mms6 protein and a synthetic C-terminal domain of mms6 protein to self-assembling polymers in order to template hierarchical CoFe2O4 nanostructures. This new synthesis pathway enables facile room-temperature shape-specific synthesis ...


Crystal Structure And Evolution Of A Prokaryotic Glucoamylase, Alexander E. Aleshin, Ping-Hua Feng, Richard B. Honzatko, Peter J. Reilly Mar 2003

Crystal Structure And Evolution Of A Prokaryotic Glucoamylase, Alexander E. Aleshin, Ping-Hua Feng, Richard B. Honzatko, Peter J. Reilly

Chemical and Biological Engineering Publications

The first crystal structures of a two-domain, prokaryotic glucoamylase were determined to high resolution from the clostridial species Thermoanaerobacterium thermosaccharolyticum with and without acarbose. The N-terminal domain has 18 antiparallel strands arranged in β-sheets of a super-β-sandwich. The C-terminal domain is an (α/α)6 barrel, lacking the peripheral subdomain of eukaryotic glucoamylases. Interdomain contacts are common to all prokaryotic Family GH15 proteins. Domains similar to those of prokaryotic glucoamylases in maltose phosphorylases (Family GH65) and glycoaminoglycan lyases (Family PL8) suggest evolution from a common ancestor. Eukaryotic glucoamylases may have evolved from prokaryotic glucoamylases by the substitution of the N-terminal ...