Approximate quantum counting on an NMR ensemble quantum computer
PHYSICAL REVIEW LETTERS 83:5 (1999) 1050-1053
Structural and dynamical characterization of a biologically active unfolded fibronectin-binding protein from Staphylococcus aureus.
Biochemistry 37:48 (1998) 17054-17067
Abstract:
A 130-residue fragment (D1-D4) taken from a fibronectin-binding protein of Staphylococcus aureus, which contains four fibronectin-binding repeats and is unfolded but biologically active at neutral pH, has been studied extensively by NMR spectroscopy. Using heteronuclear multidimensional techniques, the conformational properties of D1-D4 have been defined at both a global and a local level. Diffusion studies give an average effective radius of 26.2 +/- 0.1 A, approximately 75% larger than that expected for a globular protein of this size. Analysis of chemical shift, 3JHNalpha coupling constant, and NOE data show that the experimental parameters agree well overall with values measured in short model peptides and with predictions from a statistical model for a random coil. Sequences where specific features give deviations from these predictions for a random coil have however been identified. These arise from clustering of hydrophobic side chains and electrostatic interactions between charged groups. 15N relaxation studies demonstrate that local fluctuations of the chain are the dominant motional process that gives rise to relaxation of the 15N nuclei, with a persistence length of approximately 7-10 residues for the segmental motion. The consequences of the structural and dynamical properties of this unfolded protein for its biological role of binding to fibronectin have been considered. It is found that the regions of the sequence involved in binding have a high propensity for populating extended conformations, a feature that would allow a number of both charged and hydrophobic groups to be presented to fibronectin for highly specific binding.Quantum logic gates and nuclear magnetic resonance pulse sequences.
J Magn Reson 135:2 (1998) 353-360
Abstract:
There has recently been considerable interest in the use of nuclear magnetic resonance (NMR) as a technology for the implementation of small quantum computers. These computers operate by the laws of quantum mechanics, rather than classical mechanics and can be used to implement new quantum algorithms. Here we describe how NMR in principle can be used to implement all the elements required to build quantum computers, and draw comparisons between the pulse sequences involved and those of more conventional NMR experiments.Quantum computing [4] (multiple letters)
Science 281:5385 (1998) 1963-1964
Amyloid fibril formation by an SH3 domain.
Proc Natl Acad Sci U S A 95:8 (1998) 4224-4228