Volume 72 Number 3 May 2005	back to contents

From the 1 Departments of Physiology and Medicine, University of California, San Francisco, San Francisco, CA; and 2 Department of Pathobiology, University of Washington, Seattle, WA.

This work was supported by grants from the NIH to VRL and to JRL.

A version of this manuscript was presented by VRL as a Dean's Lecture at the Mount Sinai School of Medicine, New York City, NY on October 30, 2002, and updated as of September 2004.

Address all correspondence to V.R. Lingappa, M.D., Ph.D., Department of Physiology, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143-0444; email: vrl@itsa.ucsf.edu

ABSTRACT

We review the important role that cell-free protein-synthesizing systems (CFPSS) have played in the history of modern biology, and highlight two recent applications that illustrate their continued utility for the exploration of otherwise intractable aspects of gene expression and its regulation. Viral capsid assembly recreated in CFPSS reveals a catalyzed biochemical pathway involving transient, energy-dependent action of host proteins and discrete assembly intermediates, rather than the classical notion of self-assembly that was expected for capsid formation. Study of prion protein biogenesis reveals a new conformation critical for disease pathogenesis and advances the paradigm of protein bioconformatics , by which cells may productively regulate the folding of various proteins. In each example, the CFPSS made it easier to analyze biochemical mechanism than is possible in other currently available whole cell systems, illustrating why this approach is likely to be a continuing source of insight into important features of biological regulation.

KEYWORDS

Protein synthesis, in vitro translation, biogenesis, protein folding, viral capsid, prion, wheat germ, reticulocyte lysate, translocation, endoplasmic reticulum, translocon.

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