Structure of native laccase from Trametes hirsuta at 1.8 A resolution.

This paper describes the structural analysis of the native form of laccase from Trametes hirsuta at 1.8 A resolution. This structure provides a basis for the elucidation of the mechanism of catalytic action of these ubiquitous proteins. The 1.8 A resolution native structure provided a good level of structural detail compared with many previously reported laccase structures. A brief comparison with the active sites of other laccases is given.

How to multiply a matrix of normal equations by an arbitrary vector using FFT.

This paper describes a novel algorithm for multiplying a matrix of normal equations by an arbitrary real vector using the fast Fourier transform technique. The algorithm allows full-matrix least-squares refinement of macromolecular structures without explicit calculation of the normal matrix. The resulting equations have been implemented in a new computer program, FMLSQ. A preliminary version of the program has been tested on several protein structures. The consequences for crystallographic refinement of macromolecules are discussed in detail.

Phased translation function revisited: structure solution of the cofilin-homology domain from yeast actin-binding protein 1 using six-dimensional searches.

A modified molecular-replacement method is described that makes use of six-dimensional searches and the phased translation function, providing a systematic examination of all possible search-model orientations in an experimental electron-density map. As an example, the structure solution of the cofilin-homology domain of the Saccharomyces cerevisiae actin-binding protein 1 (ABP1) is presented in detail. Additional examples are presented in which these tools have significantly aided structure solutions in a variety of contexts. These results suggest that this approach might be of widespread utility for challenging structures involving weak phase information, complex asymmetric units and search models with weak structural homology. Furthermore, this approach supports an exhaustive molecular-replacement strategy in cases where an appropriate search model cannot readily be identified on the basis of sequence homology. The fully automated web-based implementation of this phased translation function is described.