An Interview with Matthew P. Greving, PhD. Interview by Vicki Glaser.

Matthew P. Greving is Chief Scientific Officer at Nextval Inc., a company founded in early 2010 that has developed a discovery platform called MassInsight™.

Thermodynamic additivity of sequence variations: an algorithm for creating high affinity peptides without large libraries or structural information.

Background: There is a significant need for affinity reagents with high target affinity/specificity that can be developed rapidly and inexpensively. Existing affinity reagent development approaches, including protein mutagenesis, directed evolution, and fragment-based design utilize large libraries and/or require structural information thereby adding time and expense. Until now, no systematic approach to affinity reagent development existed that could produce nanomolar affinity from small chemically synthesized peptide libraries without the aid of structural information.

Nanostructure-initiator mass spectrometry metabolite analysis and imaging.

Nanostructure-Initiator Mass Spectrometry (NIMS) is a matrix-free desorption/ionization approach that is particularly well-suited for unbiased (untargeted) metabolomics. An overview of the NIMS technology and its application in the detection of biofluid and tissue metabolites are presented. (To listen to a podcast about this feature, please go to the Analytical Chemistry multimedia page at pubs.

Discovery of high-affinity protein binding ligands--backwards.

Background: There is a pressing need for high-affinity protein binding ligands for all proteins in the human and other proteomes. Numerous groups are working to develop protein binding ligands but most approaches develop ligands using the same strategy in which a large library of structured ligands is screened against a protein target to identify a high-affinity ligand for the target. While this methodology generates high-affinity ligands for the target, it is generally an iterative process that can be difficult to adapt for the generation of ligands for large numbers of proteins.

High-throughput screening in two dimensions: binding intensity and off-rate on a peptide microarray.

We report a high-throughput two-dimensional microarray-based screen, incorporating both target binding intensity and off-rate, which can be used to analyze thousands of compounds in a single binding assay. Relative binding intensities and time-resolved dissociation are measured for labeled tumor necrosis factor alpha (TNF-alpha) bound to a peptide microarray. The time-resolved dissociation is fitted to a one-component exponential decay model, from which relative dissociation rates are determined for all peptides with binding intensities above background.

Feature-level MALDI-MS characterization of in situ-synthesized peptide microarrays.

Characterizing the chemical composition of microarray features is a difficult yet important task in the production of in situ-synthesized microarrays. Here, we describe a method to determine the chemical composition of microarray features, directly on the feature. This method utilizes nondiffusional chemical cleavage from the surface along with techniques from MALDI-MS tissue imaging, thereby making the chemical characterization of high-density microarray features simple, accurate, and amenable to high-throughput.