Pin1 is an essential peptidyl-prolyl isomerase (PPIase) that catalyzes cis-trans prolyl isomerization in proteins containing phosphorylated serine/threonine-proline motifs (pSer/Thr-Pro). It has an N-terminal binding domain (WW) and a C-terminal PPIase domain. Pin1 targets pSer/Thr-Pro motifs by its WW domain and catalyzes isomerization through its PPIase domain. This dissertation is focused on elucidating the interactions between Pin1/substrate, the inter-domain dynamics upon binding, and the catalytic activity of Pin1 upon binding different substrates. Specifically, we investigated the Pin1-Histone H1 interaction and designed a series of chimeric peptides based on the H1.4 sequence (KATGAApTPKKSAKW). NMR titrations were performed for each peptide using both full-length Pin1 as well as the WW domain alone, to analyze the binding affinities. Here we combined 15N relaxation and residual dipolar couplings (RDCs) to monitor the degree to which peptide binding induced inter-domain interactions. We also investigated whether our chimeric sequences could alter catalysis (kex) using 1H-1H EXSY NMR experiments. Finally, when combined with molecular modeling, our results suggest a structural basis for how substrate binding can alter Pin1 inter-domain dynamics..

Pin1 is a Prolyl Isomerase that catalyzes cis-trans isomerization of peptides with pSer/Thr-Pro motifs in many cell signaling proteins. This conformational switch is implicated in diseases. Pin1 activity is considered a target for therapeutic applications. Pin1 targets motifs by its N-terminal WW-binding domain. A C-terminal PPIase domain is responsible for catalysis. To understand how Pin1 coordinates its enzymatic activities, it is necessary to probe how the domains behave in the presence of substrates. Here, we used novel (Histone H1 and Sic1) and other existing peptides to characterize the dynamics of Pin1 and impact of substrate binding on inter-domain interactions. Pin1-peptide complexes have been used to show that peptide addition causes a conformational change in the two domains. 15N-relaxation data suggest that the flexibility of these domains depends on the substrate peptide We have constructed a hypothesis about which substrate residues may be important for conferring tight binding and inter-domain interactions.

Nuclear Magnetic Resonance (NMR) spectroscopy is the most powerful technique for characterization of biomolecular structures at atomic resolution in the solution state. This timely book, entitled "Biomolecular NMR Spectroscopy," focuses on the latest state-of-the-art NMR techniques for characterization of biological macromolecules in the solid and solution state. The editors, Dr. Andrew Dingley (University of Auckland, New Zealand) and Dr. Steven Pascal (Massey University, New Zealand) have organized the book into four sections, covering the following topics: sample preparation, structure and dynamics of proteins, structure and dynamics of nucleic acids and protein-nucleic acid complexes, and rapid and hybrid techniques--

Weak acids and based; Amino acids and peptides; Biochemical energetics; Enzyme kinetics; Spectrophotometry; Isotopes in biochemistry; Miscellaneous calculations.

This book discusses how biological molecules exert their function and regulate biological processes, with a clear focus on how conformational dynamics of proteins are critical in this respect. In the last decade, the advancements in computational biology, nuclear magnetic resonance including paramagnetic relaxation enhancement, and fluorescence-based ensemble/single-molecule techniques have shown that biological molecules (proteins, DNAs and RNAs) fluctuate under equilibrium conditions. The conformational and energetic spaces that these fluctuations explore likely contain active conformations that are critical for their function. More interestingly, these fluctuations can respond actively to external cues, which introduces layers of tight regulation on the biological processes that they dictate. A growing number of studies have suggested that conformational dynamics of proteins govern their role in regulating biological functions, examples of this regulation can be found in signal transduction, molecular recognition, apoptosis, protein / ion / other molecules translocation and gene expression. On the experimental side, the technical advances have offered deep insights into the conformational motions of a number of proteins. These studies greatly enrich our knowledge of the interplay between structure and function. On the theoretical side, novel approaches and detailed computational simulations have provided powerful tools in the study of enzyme catalysis, protein / drug design, protein / ion / other molecule translocation and protein folding/aggregation, to name but a few. This work contains detailed information, not only on the conformational motions of biological systems, but also on the potential governing forces of conformational dynamics (transient interactions, chemical and physical origins, thermodynamic properties). New developments in computational simulations will greatly enhance our understanding of how these molecules function in various biological events.

Christopher M. Cheatum and Amnon Kohen, Relationship of Femtosecond–Picosecond Dynamics to Enzyme-Catalyzed H-Transfer. Cindy Schulenburg and Donald Hilvert, Protein Conformational Disorder and Enzyme Catalysis. A. Joshua Wand, Veronica R. Moorman and Kyle W. Harpole, A Surprising Role for Conformational Entropy in Protein Function. Travis P. Schrank, James O. Wrabl and Vincent J. Hilser, Conformational Heterogeneity Within the LID Domain Mediates Substrate Binding to Escherichia coli Adenylate Kinase: Function Follows Fluctuations. Buyong Ma and Ruth Nussinov, Structured Crowding and Its Effects on Enzyme Catalysis. Michael D. Daily, Haibo Yu, George N. Phillips Jr and Qiang Cui, Allosteric Activation Transitions in Enzymes and Biomolecular Motors: Insights from Atomistic and Coarse-Grained Simulations. Karunesh Arora and Charles L. Brooks III, Multiple Intermediates, Diverse Conformations, and Cooperative Conformational Changes Underlie the Catalytic Hydride Transfer Reaction of Dihydrofolate Reductase. Steven D. Schwartz, Protein Dynamics and the Enzymatic Reaction Coordinate.