Facile synthesis of metal-chelating peptides on chip for protein array

Miniaturized and Automated Synthesis of Biomolecules-Overview and Perspectives

Chemical synthesis is performed by reacting different chemical building blocks with defined stoichiometry, while meeting additional conditions, such as temperature and reaction time. Such a procedure is especially suited for automation and miniaturization. Life sciences lead the way to synthesizing millions of different oligonucleotides in extremely miniaturized reaction sites, e.g., pinpointing active genes in whole genomes, while chemistry advances different types of automation. Recent progress in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) imaging could match miniaturized chemical synthesis with a powerful analytical tool to validate the outcome of many different synthesis pathways beyond applications in the life sciences. Thereby, due to the radical miniaturization of chemical synthesis, thousands of molecules can be synthesized. This in turn should allow ambitious research, e.g., finding novel synthesis routes or directly screening for photocatalysts. Herein, different technologies are discussed that might be involved in this endeavor. A special emphasis is given to the obstacles that need to be tackled when depositing tiny amounts of materials to many different extremely miniaturized reaction sites.

Protein microarray using alpha-amino acids as metal tags on chips

Procedures for synthesizing alpha-amino acids on a chip for coordination with transitional metal ions and a His-Tagged protein have been successfully developed as a stable protein microarray. Using the recombinant His-Tagged 3CL-protease (3CLpro) as a model for attachment to chips containing D-/L-Glu, Asp, Orn, Ser via different transitional metal ions, it was found that the Orn chip was the best of affinity binding and stability by which Zn2+ was the best metal ion for affinity while Co2+ was the best metal ion for stability. Thus, this protein microarray can be alternatively used as a high throughput screening method for rapid detection against SARS CoV 3CLpro and/or efficient purification of other Tagged proteins.

Derivatization of phosphopeptides with mercapto- and amino-functionalized conjugate groups by phosphate elimination and subsequent Michael addition

Kinetics of the beta-elimination of the phosphate group from H-Tyr-Ser(PO3H2)-Phe-OH and H-Tyr-Thr(PO3H2)-Phe-OH and subsequent addition of thiols and amines to the dehydroalaninyl and beta-methyldehydroalaninyl residues formed, were followed by RP HPLC under alkaline conditions in the absence and presence of Ba2+ ions. By this reaction sequence, the phosphoserinyl peptide was conjugated with mono-N-(2-mercaptoethyl)amide of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (4), a mercapto-functionalized pentapeptide, H-His-Gly-Gly-His-Gly-NH(CH2)4SH, and an amino-functionalized fluorescent dye, 5-dimethylaminonaphthalene-1-[N-(5-aminopentyl)]sulfonamide (dansyl cadaverine). The beta-methyldehydroalanine residue was, in turn, observed to be a poor Michael acceptor.