Identification and characterization of peptide fragments for the direct and site-specific immobilization of functional proteins onto the surface of silicon nitride.

In this study, we successfully identified peptide fragments that have a strong affinity toward the surface of a silicon nitride (SiN) substrate. An E. coli soluble protein, which was preferentially adsorbed onto the surface of a SiN substrate was isolated by 2D electrophoresis, and it was identified as "elongation factor Tu (ELN)" via the peptide MS fingerprinting method.

Controlling protein crystal nucleation by droplet-based microfluidics.

Herein, we demonstrate the potential of droplet-based microfluidics for controlling protein crystallization and generating single-protein crystals. We estimated the critical droplet size for obtaining a single crystal within a microdroplet and investigated the crystallization of four model proteins to confirm the effect of protein molecular diffusion on crystallization. A single crystal was obtained in microdroplets smaller than the critical size by using droplet-based microfluidics.

X-ray diffraction of protein crystal grown in a nano-liter scale droplet in a microchannel and evaluation of its applicability.

We describe the technical aspects of the in-situ X-ray diffraction of a protein crystal prepared by a nanodroplet-based crystallization method. We were able to obtain diffraction patterns from a crystal grown in a capillary without any manipulation. Especially in our experimental approach, the crystals that moved to the nanodroplet interface were fixed strongly enough to carry out X-ray diffraction measurements that could be attributed to the high surface tension of the nanodroplet.