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Protein Engineering, Design & Selection: PEDS

Marco Mravic, Hailin Hu, Zhenwei Lu, Joel S Bennett, Charles R Sanders, A Wayne Orr, William F DeGrado
Computationally designed transmembrane α-helical peptides (CHAMP) have been used to compete for helix-helix interactions within the membrane, enabling the ability to probe the activation of the integrins αIIbβ3 and αvβ3. Here, this method is extended towards the design of CHAMP peptides that inhibit the association of the α5β1 transmembrane (TM) domains, targeting the Ala-X3-Gly motif within α5. Our previous design algorithm was performed alongside a new workflow implemented within the widely used Rosetta molecular modeling suite...
July 10, 2018: Protein Engineering, Design & Selection: PEDS
Matthew Carter Childers, Clare-Louise Towse, Valerie Daggett
Computational resources have contributed to the design and engineering of novel proteins by integrating genomic, structural and dynamic aspects of proteins. Non-canonical amino acids, such as d-amino acids, expand the available sequence space for designing and engineering proteins; however, the rotamer libraries for d-amino acids are usually constructed as the mirror images of l-amino acid rotamer libraries, an assumption that has not been tested. To this end, we have performed molecular dynamics (MD) simulations of model host-guest peptide systems containing d-amino acids...
July 10, 2018: Protein Engineering, Design & Selection: PEDS
Roberto De Luca, Paul Kachel, Klara Kropivsek, Berend Snijder, Markus G Manz, Dario Neri
A novel dual-cytokine-antibody fusion protein, consisting of an antibody directed against CD38 [a tumor-associated antigen mainly expressed on the surface of multiple myeloma (MM) cells], simultaneously fused to both tumor necrosis factor ligand superfamily member 10 (TRAIL) and interleukin-2 (IL2), was designed, expressed and purified to homogeneity. The novel fusion protein, termed IL2-αCD38-αCD38-scTRAIL, was able to selectively recognize its cognate antigen expressed on the surface of MM and lymphoma cell lines, as evidenced by flow cytometry analysis...
July 5, 2018: Protein Engineering, Design & Selection: PEDS
Sudeep Karki, Prodeep Paudel, Celeste Sele, Alexander V Shkumatov, Tommi Kajander
Synaptic adhesion molecules play a crucial role in the regulation of synapse development and maintenance. Recently, several families of leucine-rich repeat (LRR) domain-containing neuronal adhesion molecules have been characterised, including netrin-G ligands, LRRTMs and the synaptic adhesion-like molecule (SALM) family proteins. Most of these are expressed at the excitatory glutamatergic synapses, and dysfunctions of these genes are genetically linked with cognitive disorders, such as autism spectrum disorders and schizophrenia...
June 12, 2018: Protein Engineering, Design & Selection: PEDS
Raiji Kawade, Hiroki Akiba, Kevin Entzminger, Toshiaki Maruyama, C J Okumura, Kouhei Tsumoto
Rabbit antibodies show unique structural characteristics in that kappa chains have an inter-domain disulfide bond between the variable and constant domains. Here we characterized this disulfide bond from physicochemical viewpoints both in stability and affinity. It was revealed that the disulfide bond contributed to the thermal stability of the antibody, but the affinity and mechanism of antigen recognition was not altered by the mutation. The present result expands the understanding of how rabbit antibodies with kappa light chains gain affinity under characteristic mechanism to gain thermal stability, and would give suggestions for the methods to artificially stabilize antibody molecules...
May 30, 2018: Protein Engineering, Design & Selection: PEDS
L Schwaigerlehner, M Pechlaner, P Mayrhofer, C Oostenbrink, R Kunert
Humanized monoclonal antibodies (mAbs) are among the most promising modern therapeutics, but defined engineering strategies are still not available. Antibody humanization often leads to a loss of affinity, as it is the case for our model antibody Ab2/3H6 (PDB entry 3BQU). Identifying appropriate back-to-mouse mutations is needed to restore binding affinity, but highly challenging. In order to get more insight, we have applied molecular dynamics simulations and correlated them to antibody binding and expression in wet lab experiments...
May 11, 2018: Protein Engineering, Design & Selection: PEDS
Maike Lenz, Silvia Fademrecht, Mahima Sharma, Jürgen Pleiss, Gideon Grogan, Bettina M Nestl
We report the exploration of the evolutionary relationship between imine reductases (IREDs) and other dehydrogenases. This approach is informed by the sequence similarity between these enzyme families and the recently described promiscuous activity of IREDs for the highly reactive carbonyl compound 2,2,2-trifluoroacetophenone. Using the structure of the R-selective IRED from Streptosporangium roseum (R-IRED-Sr) as a model, β-hydroxyacid dehydrogenases (βHADs) were identified as the dehydrogenases most similar to IREDs...
May 3, 2018: Protein Engineering, Design & Selection: PEDS
Xiufeng Wu, Richard Yuan, Michael Bacica, Stephen J Demarest
The clinical success of monoclonal antibodies to treat diseases across nearly every therapeutic area has spurred advances in bispecific antibody technology with the goal of cost-effectively combining various therapies or providing novel mechanisms for disease intervention. Many novel bispecific antibodies are now in clinical development or the late pre-clinical setting. A new horizon exists for novel molecular entities with the ability to bind three or more antigens. Here we describe the production and characterization of novel trispecific antibody-like proteins denoted 'OrthoTsAbs' that self-assemble through the application of engineered antibody domain interfaces...
April 28, 2018: Protein Engineering, Design & Selection: PEDS
Harun F Ozbakir, Kristen E Garcia, Scott Banta
Enzymatic biocatalysis can be limited by the necessity of soluble cofactors. Here, we introduced PEGylated nicotinamide adenine dinucleotide (NAD(H)) swing arms to two covalently fused dehydrogenase enzymes to eliminate their nicotinamide cofactor requirements. A formate dehydrogenase and cytosolic malate dehydrogenase were connected via SpyCatcher-SpyTag fusions. Bifunctionalized polyethylene glycol chains tethered NAD(H) to the fusion protein. This produced a formate:malate oxidoreductase that exhibited cofactor-independent ping-pong kinetics with predictable Michaelis constants...
April 5, 2018: Protein Engineering, Design & Selection: PEDS
Jennifer I Lai, Deeptak Verma, Chris Bailey-Kellogg, Margaret E Ackerman
Structure-based approaches to antigen design utilize insights from antibody (Ab):antigen interactions and a refined understanding of protective Ab responses to engineer novel antigens presenting epitopes with conformations relevant to eliciting or discovering protective humoral responses. For human immunodeficiency virus-1 (HIV-1), one model of protection is provided by broadly neutralizing Abs (bnAbs) against epitopes present in the closed prefusion trimeric conformation of HIV-1 envelope glycoprotein, such as the variable loops 1-2 (V1V2) apex...
April 1, 2018: Protein Engineering, Design & Selection: PEDS
Mitesh Nagar, Himank Kumar, Stephen L Bearne
Mandelate racemase (MR) serves as a paradigm for our understanding of enzyme-catalyzed deprotonation of a carbon acid substrate. To facilitate structure-function studies on MR using non-natural amino acid substitutions, we engineered the Cys92Ser/Cys264Ser variant (dmMR) as a platform for introducing Cys residues at specific locations for subsequent covalent modification. While the highly reactive thiol of Cys furnishes a site for chemical modification, site-specificity requires that other Cys residues be non-reactive or replaced by a non-reactive amino acid, especially if chemical modification is conducted under denaturing conditions...
April 1, 2018: Protein Engineering, Design & Selection: PEDS
S Palikša, G Alzbutas, R Skirgaila
Personalized medicine and advanced diagnostic tools based on RNA analysis are focusing on fast and direct One-Step RT-PCR assays. First strand complementary DNA (cDNA) synthesized by the reverse transcriptase (RT) is exponentially amplified in the end-point or real-time PCR. Even a minor discrepancy in PCR conditions would result in big deviations during the data analysis. Thus, One-Step RT-PCR composition is typically based on the PCR buffer. In this study, we have used compartmentalized ribosome display technique for in vitro evolution of the Moloney Murine Leukemia Virus reverse transcriptase (M-MuLV RT) that would be able to perform efficient full-length cDNA synthesis in PCR buffer optimized for Thermus aquaticus DNA polymerase...
March 1, 2018: Protein Engineering, Design & Selection: PEDS
Annalee W Nguyen, Kevin C Le, Jennifer A Maynard
Discovery of monoclonal antibodies is most commonly performed using phage or yeast display but mammalian cells are used for production because of the complex antibody structure, including the multiple disulfide bonds and glycosylation, required for function. As this transition between host organisms is often accompanied by impaired binding, folding or expression, development pipelines include laborious plate-based screening or engineering strategies to adapt an antibody to mammalian expression. To circumvent these problems, we developed a plasmid-based Fab screening platform on Chinese hamster ovary (CHO) cells which allows for antibody selection in the production host and in the presence of the same post-translational modifications as the manufactured product...
March 1, 2018: Protein Engineering, Design & Selection: PEDS
Nicolás Palopoli, Nicolás S González Foutel, Toby J Gibson, Lucía B Chemes
Pocket proteins retinoblastoma (pRb), p107 and p130 are negative regulators of cellular proliferation and multifunctional proteins regulating development, differentiation and chromatin structure. The retinoblastoma protein is a potent tumor suppressor mutated in a wide range of human cancers, and oncogenic viruses often interfere with cell cycle regulation by inactivating pRb. The LxCxE and pRb AB groove short linear motifs (SLiMs) are key to many pocket protein mediated interactions including host and viral partners...
March 1, 2018: Protein Engineering, Design & Selection: PEDS
Boudhayan Bandyopadhyay, Yoav Peleg
Circular permutation is a powerful tool to test the role of topology in protein folding and function. Previous methods for generating circular permutants were based on rearranging gene elements using restriction enzymes-based cloning. Here, we present a Restriction Free (RF) approach to achieve circular permutation which is faster and more cost-effective.
March 1, 2018: Protein Engineering, Design & Selection: PEDS
Zhuo Yang, Mingjuan Du, Wei Wang, Xiu Xin, Peixiang Ma, Hongkai Zhang, Richard A Lerner
It has been observed that converting scFv formatted antibodies to full-length IgG often associates with loss of affinity. We aim to address this issue in this paper by establishing an integrated affinity maturation method applying yeast display technology platform. To demonstrate that, we employed a human thrombopoietin receptor targeting antibody named 3D9 which was identified previously from a combinational antibody library in scFv-Fc fusion protein form. We have observed that significant potency loss happened when 3D9 was transformed to full-length IgG form...
February 21, 2018: Protein Engineering, Design & Selection: PEDS
Andrew K D Younger, Peter Y Su, Andrea J Shepard, Shreya V Udani, Thaddeus R Cybulski, Keith E J Tyo, Joshua N Leonard
Naturally evolved metabolite-responsive biosensors enable applications in metabolic engineering, ranging from screening large genetic libraries to dynamically regulating biosynthetic pathways. However, there are many metabolites for which a natural biosensor does not exist. To address this need, we developed a general method for converting metabolite-binding proteins into metabolite-responsive transcription factors-Biosensor Engineering by Random Domain Insertion (BERDI). This approach takes advantage of an in vitro transposon insertion reaction to generate all possible insertions of a DNA-binding domain into a metabolite-binding protein, followed by fluorescence activated cell sorting to isolate functional biosensors...
February 1, 2018: Protein Engineering, Design & Selection: PEDS
D Sussman, L Westendorf, D W Meyer, C I Leiske, M Anderson, N M Okeley, S C Alley, R Lyon, R J Sanderson, P J Carter, D R Benjamin
Antibody-drug conjugates (ADCs) are fulfilling the promise of targeted therapy with meaningful clinical success. An intense research effort is directed towards improving pharmacokinetic profiles, toxicity and chemical stability of ADCs. The majority of ADCs use amide and thioether chemistry to link potent cytotoxic agents to antibodies via endogenous lysine and cysteine residues. While maleimide-cysteine conjugation is used for many clinical stage ADC programs, maleimides have been shown to exhibit some degree of post-conjugation instability...
February 1, 2018: Protein Engineering, Design & Selection: PEDS
Malgorzata Figiel, Piotr Bonarek, Andrzej Górecki, Sebastian D Pawlak, Bartlomiej Zerek, Beata Checinska, Jerzy Pieczykolan, Marta Dziedzicka-Wasylewska
The TNF-Related Apoptosis Inducing Ligand (TRAIL) cytokine triggers apoptosis specifically in cancer cells. Susceptibility of a given cell to TRAIL depends on the activity of regulatory proteins, one of the most important of which is BID. The aim of this study was to increase the cytotoxic potential of TRAIL against cancer cells. TRAIL was fused to the BH3 domain of BID. Hence, TRAIL acted not only as an anticancer agent, but also as a specific carrier for the BID fragment. Two fusion protein variants were obtained by genetic engineering, harboring two different linker sequences...
February 1, 2018: Protein Engineering, Design & Selection: PEDS
Maho Yagi-Utsumi, Arunima Sikdar, Toshiya Kozai, Rintaro Inoue, Masaaki Sugiyama, Takayuki Uchihashi, Hirokazu Yagi, Tadashi Satoh, Koichi Kato
Recent bioinformatic analyses identified proteasome assembly chaperone-like proteins, PbaA and PbaB, in archaea. PbaB forms a homotetramer and functions as a proteasome activator, whereas PbaA does not interact with the proteasome despite the presence of an apparent C-terminal proteasome activation motif. We revealed that PbaA forms a homopentamer predominantly in the closed conformation with its C-terminal segments packed against the core domains, in contrast to the PbaB homotetramer with projecting C-terminal segments...
January 1, 2018: Protein Engineering, Design & Selection: PEDS
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