MCLS, Emerald and Crystal Structures.
I read the article which is very interesting, but wondered aloud if they had really achieved high throughput.
Not to denigrate, but the Topo structure is not a recent 'win' though it clearly was the basis of the acquistion by MCLS.
1: Science 1998 Mar 6;279(5356):1534-41 Related Articles, Books, Protein, Nucleotide, Structure, LinkOut
Comment in:
Science. 1998 Mar 6;279(5356):1490-1
A model for the mechanism of human topoisomerase I.
Stewart L, Redinbo MR, Qiu X, Hol WG, Champoux JJ.
Biomolecular Structure Center and Department of Biological Structure, School of Medicine, University of Washington, Seattle, WA 98195-7742, USA. emerald_biostructures@rocketmail.com
The three-dimensional structure of a 70-kilodalton amino terminally truncated form of human topoisomerase I in complex with a 22-base pair duplex oligonucleotide, determined to a resolution of 2.8 angstroms, reveals all of the structural elements of the enzyme that contact DNA. The linker region that connects the central core of the enzyme to the carboxyl-terminal domain assumes a coiled-coil configuration and protrudes away from the remainder of the enzyme. The positively charged DNA-proximal surface of the linker makes only a few contacts with the DNA downstream of the cleavage site. In combination with the crystal structures of the reconstituted human topoisomerase I before and after DNA cleavage, this information suggests which amino acid residues are involved in catalyzing phosphodiester bond breakage and religation. The structures also lead to the proposal that the topoisomerization step occurs by a mechanism termed "controlled rotation."
PMID: 9488652 [PubMed - indexed for MEDLINE]
And then, some more work on it:
1: J Mol Biol 1999 Sep 24;292(3):685-96 Related Articles, Books, LinkOut
Structural flexibility in human topoisomerase I revealed in multiple non-isomorphous crystal structures.
Redinbo MR, Stewart L, Champoux JJ, Hol WG.
Department of Biological Structure, School of Medicine, University of Washington, Seattle, WA 98195, USA.
Human topoisomerase I plays a critical role in chromosomal stability by relaxing the DNA superhelical tension that arises from a variety of nuclear processes, including replication, transcription, and chromatin remodeling. Human topoisomerase I is a approximately 91 kDa enzyme composed of four major domains: a 24 kDa N-terminal domain, a56 kDa core domain, a7 kDa linker domain, and a6 kDa C-terminal domain containing the active-site Tyr723 residue. A monoclinic crystal structure of a 70 kDa N-terminally truncated form of human topoisomerase I in non-covalent complex with a 22 bp DNA duplex exhibited remarkable crystal-to-crystal non-isomorphism; shifts in cell constants of up to 9 A in the b -axis length and up to 8.5 degrees in the beta-angle were observed. Eight crystal structures of human topoisomerase I - DNA complexes from this crystal form were determined to between 2.8 and 3.25 A resolution. These structures revealed both dramatic shifts in crystal packing and functionally suggestive regions of conformational flexibility in the structure of the enzyme. Crystal packing shifts of up to 20.5 A combined with rotations of up to 11.5 degrees were observed, helping to explain the variability in cell constants. When the core subdomain III regions of the eight structures are superimposed, the "cap" (core subdomains I and II) of the molecule is observed to rotate by up to 4.6 degrees and to shift by up to 3.6 A. The linker domain shows the greatest degree of conformational flexibility, rotating and shifting by up to 2.5 degrees and 4.6 A, respectively, in five of eight structures, and becoming disordered altogether in the remaining three. These observed regions of conformational flexibility in the cap and the linker domain are consistent with the structural flexibility invoked in the "controled rotation" mechanism proposed for the relaxation of DNA superhelical tension by human topoisomerase I. Copyright 1999 Academic Press.
PMID: 10497031 [PubMed - indexed for MEDLINE]
And still more. Well, you get the picture.
ncbi.nlm.nih.gov
Sounds like outstanding, extraordinary science and sweaty efforts. But is it HTP? And how come no publications abut the other 39 resolved crystals?
[Not that it has anything to do with the company, but I lived 7 years on BI, and I can tell you that the next most technologically advanced business on the island is the Sage Flyrod Company, and that the best businesses to be in are residential real estate and espresso. But I suppose once you pack your crystals to send across town you might as well send them as far away as Argonne, so I suppose it doesn't matter where you live.]
Nevertheless, I am now very interested in the claim to the other 39 structures. I think I'll see if MCLS answers its phone or uses voicemail.
Anyone who knows this company well and has already had a good laugh, kindly stop me from making a greater fool of myself by chirping in.
Wilder |
