• Two types of amorphous protein particles facilitate crystal nucleation

Yamazaki, Tomoya

Kimura, Yuki

Vekilov, Peter G.

Furukawa, Erika

Shirai, Manabu

Matsumoto, Hiroaki

Van Driessche, Alexander E. S.

Tsukamoto, Katsuo

  • Other nucleation
  • Other protein
  • Other lysozyme
  • Other transmission electron microscopy
  • Other in situ observation
  • Nucleation, the primary step in crystallization, dictates the number of crystals, the distribution of their sizes, the polymorph selection, and other crucial properties of the crystal population. We used timeresolved liquid-cell transmission electron microscopy (TEM) to perform an in situ examination of the nucleation of lysozyme crystals. Our TEM images revealed that mesoscopic clusters, which are similar to those previously assumed to consist of a dense liquid and serve as nucleation precursors, are actually amorphous solid particles (ASPs) and act only as heterogeneous nucleation sites. Crystalline phases never form inside them. We demonstrate that a crystal appears within a noncrystalline particle assembling lysozyme on an ASP or a container wall, highlighting the role of heterogeneous nucleation. These findings represent a significant departure from the existing formulation of the two-step nucleation mechanism while reaffirming the role of noncrystalline particles. The insights gained may have significant implications in areas that rely on the production of protein crystals, such as structural biology, pharmacy, and biophysics, and for the fundamental understanding of crystallization mechanisms.
PublisherNational Academy of Sciences.
Date Issued 2017-01-10
NIItypejournal article
Identifier URI
  • isIdenticalTo DOI
    • ISSN 0027-8424
    • Proceedings of the National Academy of Sciences of the United States of America (PNAS)
    114(9), 2154-2159