Enzymes fold into unique three-dimensional structures, which underlie their remarkable catalytic properties. The requirement to adopt a stable, folded conformation is likely to contribute to their ...relatively large size (>10,000 Da). However, much shorter peptides can achieve well-defined conformations through the formation of amyloid fibrils. To test whether short amyloid-forming peptides might in fact be capable of enzyme-like catalysis, we designed a series of seven-residue peptides that act as Zn(2+)-dependent esterases. Zn(2+) helps stabilize the fibril formation, while also acting as a cofactor to catalyse acyl ester hydrolysis. These results indicate that prion-like fibrils are able to not only catalyse their own formation, but they can also catalyse chemical reactions. Thus, they might have served as intermediates in the evolution of modern-day enzymes. These results also have implications for the design of self-assembling nanostructured catalysts including ones containing a variety of biological and non-biological metal ions.
Design of a new catalytic function in proteins, apart from its inherent practical value, is important for fundamental understanding of enzymatic activity. Using a computationally inexpensive, ...minimalistic approach that focuses on introducing a single highly reactive residue into proteins to achieve catalysis we converted a 74-residue-long C-terminal domain of calmodulin into an efficient esterase. The catalytic efficiency of the resulting stereoselective, allosterically regulated catalyst, nicknamed AlleyCatE, is higher than that of any previously reported de novo designed esterases. The simplicity of our design protocol should complement and expand the capabilities of current state-of-art approaches to protein design. These results show that even a small nonenzymatic protein can efficiently attain catalytic activities in various reactions (Kemp elimination, ester hydrolysis, retroaldol reaction) as a result of a single mutation. In other words, proteins can be just one mutation away from becoming entry points for subsequent evolution.
It only takes one mutation: A strategically placed single mutation in a non‐enzymatic protein scaffold produced AlleyCat, a small, allosterically regulated catalyst of Kemp elimination. In only seven ...rounds of directed evolution the enzymatic efficiency of the original 74 amino acid residue catalyst was improved more than 220‐fold to achieve a kcat value higher than that of catalytic antibodies for the same reaction, still preserving allosteric regulation.
The reaction of Salen‐like ZnII and NiII precursors with carbacylamidophosphate lanthanide moieties yields six new types of 3d–4f compounds. The complexes were characterized by means of 1H, 31P NMR ...and IR spectroscopy, elemental analysis, ESI mass spectrometry, and X‐ray diffraction analysis. Depending on the Schiff base ligands, the NiII ion adopts either a square‐planar or an octahedral geometry, whereas the ZnII ion has a tetragonal‐pyramidal geometry. The coordination number of lanthanides is nine or ten. Hydrolytic activities of some heterobimetallic Zn–Ln and Ni–Ln coordination compounds in the reaction of intramolecular hydrolytic degradation of the 2‐(hydroxypropyl)‐p‐nitrophenyl phosphate were investigated.
Synthesis and crystal studies of new binuclear 3d–4f complexes based on lanthanide motifs with carbacylamidophosphate ligands and moieties of ZnII and NiII with Schiff bases were carried out. The ability of the system to catalyze the intramolecular transesterification of 2‐(hydroxypropyl)‐p‐nitrophenyl phosphate, which is extensively employed as an RNA model substrate, was tested.
We employed a minimalist approach for design of an allosterically controlled retroaldolase. Introduction of a single lysine residue into the nonenzymatic protein calmodulin led to a 15,000‐fold ...increase in the second order rate constant for retroaldol reaction with methodol as a substrate. The resulting catalyst AlleyCatR is active enough for subsequent directed evolution in crude cell bacterial lysates. AlleyCatR's activity is allosterically regulated by Ca2+ ions. No catalysis is observed in the absence of the metal ion. The increase in catalytic activity originates from the hydrophobic interaction of the substrate (∼2000‐fold) and the change in the apparent pKa of the active lysine residue.
We recently reported that a computationally designed catalyst nicknamed AlleyCat facilitates C–H proton abstraction in Kemp elimination at neutral pH in a selective and calcium-dependent fashion by a ...factor of approximately 100,000 (Korendovych et al. in
Proc. Natl. Acad. Sci. USA
108:6823,
2011
). Kemp elimination produced a colored product that can be easily read out, thus making AlleyCat a catalytically amplified metal sensor for calcium. Here we report that metal-binding EF-hand motifs in AlleyCat could be redesigned to incorporate trivalent metal ions without significant loss of catalytic activity. Mutation of a single neutral residue at position 9 of each of the EF-hands to glutamate results in almost a two orders of magnitude improvement of selectivity for trivalent metal ions over calcium. Development of this new lanthanide-dependent switchable Kemp eliminase, named CuSeCat EE, provides the foundation for further selectivity improvement and broadening the scope of the repertoire of metals for sensing. A concerted effort in the design of switchable enzymes has many environmental, sensing, and metal ion tracking applications.
In the title complex, Cu(C8H11NO5PS)(C18H15P)2, the Cu(I) ion is coordinated by two tri-phenyl-phosphane mol-ecules and two O atoms of the chelating dimeth-yl(phenyl-sulfon-yl)amido-phosphate anion, ...generating a squashed CuO2P2 tetrahedron. In the six-membered chelate ring, the Cu, P and O atoms are almost coplanar (r.m.s. deviation = 0.024 Å), with the N and S atoms displaced in the same direction, by 0.708 (5) and 0.429 (2) Å, respectively.
In the molecular structure of the title compound, NaNi(C18H18N2O4)(NO3)(CH3OH), the Ni(2+) ion has a slightly distorted square-planar coordination environment defined by two N and two O atoms which ...belong to a Schiff base ligand, viz. 6,6'-dimeth-oxy-2,2'-ethane-1,2-diylbis(nitrilo-methanylyl-idene)diphenolate. Seven O atoms form the coordination environment of the Na(+) ion: four from the Schiff base ligand, two from a bidentate chelating nitrate anion and one O atom from a coordinating methanol mol-ecule. In the crystal, the bimetallic complexes are assembled into chains along the b-axis direction via weak C-H⋯O hydrogen-bond inter-actions. Neighbouring chains are in turn connected through bifurcated O-H⋯O hydrogen bonds that involve the coordinating methanol mol-ecules and the nitrate anions, and through π-π stacking inter-actions between phenyl rings of neighbouring mol-ecules.
► Synthesis of sulfonylamidophosphates and their sodium salts. ► Characterization of the synthesized compounds by IR, 1H, 31P NMR spectra. ► Structural investigations of three of the synthesized ...compounds.
Sulfonylamidophosphates with formula PhSO2NHP(O)(OR)2 (HL1: R=PhCH2; HL2: R=p-MeC6H4) and (p-C6H4SO2NHP(O)(OMe)2)2 (H2L3) were synthesized via a three-step procedure based on Kirsanov reaction. Sodium salts NaL1, NaL2 and Na2L3 were prepared from the corresponding sulfonylamidophosphates to explore their acid nature of the imide nitrogen. The products were characterized by means of 1H, 31P NMR and IR spectroscopies and elemental analysis. Crystal structures of HL2, H2L3 and NaL2 were determined using X-ray crystallography. HL2 produces a dimeric aggregate via intermolecular hydrogen bonding. In contrast, H2L3 and NaL2 form 1D polymeric chains.
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