The data most commonly available for the determination of macromolecular structures in solution are NOE based distance estimates and spin-spin coupling constant based dihedral angle estimates. This information is, unfortunately, inherently short-range in nature. Thus, for many multidomain proteins, little information is available to accurately position weakly interacting domains with respect to each other. Recent studies of proteins aligned in dilute liquid crystalline solvents have shown the utility of measuring anisotropic spin interactions, such as residual dipolar couplings, to obtain unique long-range structural information. In this work, the latter approach is taken to explore the relative domain orientation in a two-domain fragment from the protein barley lectin. An approach based on singular value decomposition as opposed to simulated annealing is used to directly determine order tensors for each domain from residual (15)N-(1)H dipolar couplings, and the limitations of the two approaches are discussed. Comparison of the order tensor principal axis frames as separately determined for each domain indicates that the two domains are not oriented as in the crystal structure of wheat germ agglutinin, a highly homologous protein ( approximately 95% sequence identical). Furthermore, differences in the order tensor values suggest that the two domains are not statically positioned but are experiencing different reorientational dynamics and, to a large degree, may be considered to reorient independently. Data are also presented that suggest that a specific association occurs between one domain and the lipid bicelles comprising the liquid crystal solvent.

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The prevalence of the use of teams in a variety of occupations and environments has increased the importance of investigating the processes involved in their performance. However, in the past, there have been few methodologies available for the investigation of team performance. The present manuscript attempts to contribute to this area of research by describing the rationale underlying the use of computer-based simulations in research on team performance. This is followed by a review of the networked simulations that are currently being used in team-performance research. This review emphasizes the capabilities provided by the networks and the types of research concerns for which they are effective. Finally, the application of this technology to the broader study of group performance is discussed.Because teamwork is prevalent in a number of occupations (e.g., fire-fighting, aircrews, and medicine), the ability of teams to work effectively has become a vitally important issue. In fact, Watson (1990) states that the effective use of teams is "America's best hope" for competition in the worldwide marketplace. It has been noted that technological developments and global competition have placed added emphasis upon understanding the processes and performance of teams because many tasks are often beyond the mental and physical resources of one individual (Salas, Dickinson, Converse, & Tannenbaum, 1992). Cannon-Bowers, Oser, and Flanagan (1992) cite three reasons underlying the increased importance of using teams in industry. The first is that there are critical tasks that cannot be accomplished by one individual alone. The second is the belief that groups will together perform better than single individuals. Furthermore, certain critical tasks often benefit from the redundancy offered by the use ofteams (e.g., nuclear power plant operators). The third is that group structures have developed in response to the humanistic movement in industry; that is, it is argued that the use of groups and work teams increases the source of significance and responsibility of individuals in relation to their occupations. Cannon-Bowers et al. (1992) concluded, in their review of the literature on the use of work teams in industry, that "work groups are important and offer enoughThe views expressed in this paper are those ofthe authors and do not reflect the official position of the Department of the Navy, the Department of Defense, or the U.S. Government. Please address correspondence to Clint A. Bowers, Team Performance Laboratory, Psychology Department, University of Central Florida, Orlando, FL 32816. potential to warrant creative, innovative theoretical and methodological approaches to the study of their design and effectiveness" (Cannon-Bowers et al., 1992, p. 370). Despite the critical role that teams play in industry, however, science has made woefully little progress in understanding the factors that contribute to effective team performance. In fact, reviewers in this area have severely criticized the available knowledge rega...

We present heteronuclear two-dimensional methods for the analysis of the geometry of exchangeable protons on a protein-bound carbohydrate. By using a water-selective NOESY-HSQC, we observed cross-relaxation between carbohydrate hydroxyl protons and non-exchangeable ring protons in the complex of [13C6]-alpha-methyl-D-mannopyranoside with recombinant rat mannose binding protein. Using a simple kinetic model, we were able to explain the differences in the initial slopes of the resulting cross-relaxation buildup curves in terms of the geometry of the hydroxyl protons in the bound state. The hydroxyl rotamers consistent with our cross-relaxation data fit very well with predictions based on the crystal structure of MBP bound to a mannose-rich oligosaccharide. These methods should be applicable to other systems where both ligand exchange and water exchange are fast relative to the rate of cross-relaxation.

Plant lectins are useful targets for biophysical studies of protein-carbohydrate recognition, a process of general interest because of its many roles in human physiology. Here, nuclear magnetic resonance (NMR) based structural and carbohydrate binding data on a two-domain fragment of the normally four-domain barley lectin protein are presented. The structural data, while preliminary, clearly shows that the recombinantly produced simplified model system, called BLBC, retains a nativelike fold. However, unlike the full-length parent protein, which is dimeric, BLBC is shown by pulsed-field gradient NMR diffusion studies to be largely monomeric. Still, the fragment retains nativelike carbohydrate binding properties. These properties are examined in some detail using heteronuclear single quantum coherence (HSQC) NMR spectroscopy on a uniformly 15N-labeled sample. Ligand-induced chemical shift changes in the 1H-15N HSQC spectrum are monitored as 15N-labeled BLBC is titrated with increasing concentrations of the unlabeled carbohydrate, N,N',N"-triacetylchitotriose. Well-resolved resonances from the individual domains show that BLBC binds ligand at two distinct and independent ligand binding sites, one in each domain. Binding constants of (1.1 +/- 0.2) x 10(3) M-1 and (0.6 +/- 0.2) x 10(3) M-1 are determined for the B and C domain sites, respectively. These results are discussed in relation to ligand binding studies that have previously been carried out on a highly homologous protein, wheat germ agglutinin.