NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Determining the Molecular Growth Mechanisms of Protein Crystal faces by Atomic Force MicroscopyA high resolution atomic force microscopy (AFM) study had shown that the molecular packing on the tetragonal lysozyme (110) face corresponded to only one of two possible packing arrangements, suggesting that growth layers on this face were of bimolecular height (Li et al., 1998). Theoretical analyses of the packing had also indicated that growth of this face should proceed by the addition of growth units of at least tetramer size corresponding to the 43 helices in the crystal. In this study an AFM linescan technique was devised to measure the dimensions of individual growth units on protein crystal faces. The growth process of tetragonal lysozyme crystals was slowed down by employing very low supersaturations. As a result images of individual growth events on the (110) face were observed, shown by jump discontinuities in the growth step in the linescan images. The growth unit dimension in the scanned direction was obtained by suitably averaging these images. A large number of scans in two directions on the (110) face were performed and the distribution of lysozyme aggregate sizes were obtained. A variety of growth units, all of which were 43 helical lysozyme aggregates, were shown to participate in the growth process with a 43 tetramer being the minimum observed size. This technique represents a new application for AFM allowing time resolved studies of molecular process to be carried out.
Document ID
19990103146
Acquisition Source
Marshall Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Li, Huayu
(Toledo Univ. OH United States)
Nadarajah, Arunan
(Toledo Univ. OH United States)
Pusey, Marc L.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Date Acquired
August 19, 2013
Publication Date
June 22, 1998
Subject Category
Solid-State Physics
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

Available Downloads

There are no available downloads for this record.
No Preview Available