Macromolecular crystal growth as revealed by atomic force microscopy

Alexander Mcpherson,Yu.G Kuznetsov,Alexander Malkin,Marco Plomp

doi:10.1016/s1047-8477(03)00036-4

Alexander Mcpherson, Yu.G Kuznetsov + Show 2 more

Open Access

https://doi.org/10.1016/s1047-8477(03)00036-4

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Abstract

Direct visualization of macromolecular crystal growth using atomic force microscopy (AFM) has provided a powerful tool in the delineation of mechanisms and the kinetics of the growth process. It has further allowed us to evaluate the wide variety of impurities that are incorporated into crystals of proteins, nucleic acids, and viruses. We can, using AFM, image the defects and imperfections that afflict these crystals, the impurity layers that poison their surfaces, and the consequences of various factors on morphological development. All of these can be recorded under normal growth conditions, in native mother liquors, over time intervals ranging from minutes to days, and at the molecular level.

Highlights

The process of crystallization occurs in two stages, which we refer to as nucleation and growth
Because the former involves spontaneous, singular events that are unpredictable in time and place, nucleation is difficult to directly visualize and characterize by most imaging techniques, including atomic force microscopy (AFM)
On the other hand, occurs at predictable sites on the surfaces of existing crystals, and the size range and time scale are ideally suited to direct visualization and recording by AFM

Summary

Introduction

The process of crystallization occurs in two stages, which we refer to as nucleation and growth Because the former involves spontaneous, singular events that are unpredictable in time and place, nucleation is difficult to directly visualize and characterize by most imaging techniques, including atomic force microscopy (AFM). In the past several years AFM has emerged as a powerful tool for the direct imaging and analysis of crystal growth events and their associated phenomena (McPherson et al, 1995, 2000, 2001) These are of substantial interest to X-ray crystallographers because the degree of order associated with different growth mechanisms, and. The application of AFM to the study of macromolecular crystal growth has been reviewed in some detail elsewhere (McPherson et al, 2000, 2001), but a summary here of results obtained from AFM studies may provide a useful physical context for understanding many of the day-to-day observations and problems of X-ray crystallographers and those who grow protein crystals

How AFM works

Sample preparation and data acquisition

Findings

Mechanisms of crystal growth