Texas A&M University at Kingsville Department of Chemistry 700 University Blvd. MSC 161 Kingsville, TX 78363-8202 Phone: (361) 593-2914 Fax: (361) 593-3597 E-mail: br9@tamuk.edu M.A., SUNY Buffalo (1997) Ph.D., Warwick University (2001) P.D.A., Cornell University ( 2003) P.A., NTRC (2003)

I have a Bachelor's Degree (BS) in Chemistry and Biochemistry, followed by a Masters (MS) in Fourier Transform Mass Spectrometry (FTMS) (1997) in Troy Wood's research group and a doctorate (PhD) in Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) Mass Spectrometry (2001) in Peter Derrick's research group. I was also a postdoctoral associate (PDA) at Cornell University working on plant proteomics (2001-2003) before my current position at Texas A&M University - Kingsville. My current interests are based on protein networks, primarily the interactions between proteins involved in certain biosynthetic pathways. To unzip these pathways requires a multidimensional approach utilizing proteomics, metabolomics, molecular biotechnology and bioinformatics.

Current Studies

Matrix-assister laser desorption / ionization time-of-flight mass spectrometry (MALDI-TOF MS) and nanoelectrospray ionization (nESI).

The current research is centered on protein network association determination. This is achieved gradually, by beginning with determination of differentially expressed proteins globally, then once they are known, their interactions are determined and from there the entire metabolite pathway or protein-network is unzipped. A number of complimentary technologies are utilized towards this main aim.

Electro spray ionization coupled to quadruple mass analyzer [LC-MS]

LC-MS is mainly used towards metabolite profiling, where the parent mass is lower than 2 kDa. The liquid chromatography (LC) component allows simplification of complex biological mixtures and these can subsequently be mass analyzed using the single quadruple mass analyzer or dissociated using the NS potential. In many cases NSD is not an efficient means of getting precise sequence determination because of lack of precursor ion selection, however it is a very powerful tool for mass determination of low mass species.

Nanoelectrospray ionization coupled to hybrid-quadrupole mass time-of-flight analyzer [LC-MS/MS]

LC-MS/MS is the method of choice (if FTMS is unavailable) for direct protein sequencing. In this we have the ability of precursor ion-selection in which the product ions background that are obtained retain information about the precursor ion and therefore structural information can be obtained. With the appropriate charge derivative and right energy, the protein can be unzipped along its backbone, giving precise amino acid readout. nESI allows for higher sensitive with minimal use of sample. In addition to obtaining the primary amino acid information, ESI can also allow information to be gained about the secondary and tertiary states of the protein, by proton/deuterium exchange. In our laboratory, LC MS/MS is mainly used towards protein sequencing and towards protein-ligand interactions (e.g. to determine the active site of the enzyme). Although entire proteins can be electrosprayed, the common approach is to digest the protein and then sequence the fragments. Many proteolytic enzymes are available; however the most common is still trypsin. LC can either be coupled either on-line or off-line. With off-line, the samples can be further purified or fractionated and these sub fractions [LC] analyzed by MS/MS. A complimentary approach is to use Matrix-assister laser desorption / ionization time-of-flight (MALDI-TOF) mass spectrometry as a 'fast screen' and use the putative peptide mass fingerprint (PMF) or to fragment some of these tryptic ladders by post source decay to obtain mass tag (MT) and then to 'blast' the corresponding PMFs/MTs against an appropriate FASTA format database (DB) and examine the putative candidate list obtained. Any candidates from this list can be 'de novo' sequenced on the QTOF-MS platform to verify their unequivocal identity.

One of the areas of research is natural toxin drug discovery. For example some components within certain venoms have anti-stroke mediclinical properties. A multilayered approach is required to identify the proteins involoved, to sequence them and then by use of SSH cDNA libraries to clone and overexpress these for use in a pharamacutical drug discivery phase II program. In this instance proteomics, genomics, drug discovery components are involved in varying degree and the skill set.