Abiotic Stress Adaptation: Protein Folding Stability and Dynamics - Abiotic Stress: Plant Responses and Applications in Agriculture - page 3

Chapter 1
Abiotic Stress Adaptation: Protein Folding Stability and
Dynamics
Martina Ortbauer
Additional information is available at the end of the chapter
http://dx.doi.org/10.5772/53129
1. Introduction
Abiotic stress is best defined as any factor exerted by the environment on the optimal func‐
tioning of an organism. Abiotic stresses like heat, cold, freezing, drought salinity, flooding
or oxidizing agents usually cause protein dysfunction [1]. Protein folding stability is un‐
doubtedly one of the most challenging problems in organisms undergoing stress conditions.
Efficient protein repair systems and general protein stability facilitate survival upon sudden
changes in the environment. As sessile organisms plants need to adopt quickly to overcome
various environmental stresses during their lifespan. Recently, most emphasis is being di‐
rected towards an understanding of how plants recognize external conditions and initiate
protective reactions such as mechanisms through which protein function is protected and
maintained. Proteins are biological macromolecules involved in virtually every biological
process in a living system. The roles played by proteins are varied and complex. Proteins are
used for storage and transport of small molecules or ions and control the passage of mole‐
cules through the cell membranes essential for metabolic function [2]. Hormones, which
transmit information and allow the regulation of complex cellular processes, are important
regulators in responses to abiotic stress [3]. Enzymes act as catalysts and increase, with a re‐
markable specificity, the speed of chemical reactions essential to the organism's survival.
Protein function is dependent on its unique three-dimensional structure that is adopted by
the initial folding of the polypeptide chains after translation. Encoded by DNA and synthe‐
sized on ribosomes as chains of hundreds of amino acids, each protein must find its charac‐
teristic and correct fold, rather than the countless alternatives, in order to function properly
[4]. Folding into its native and active structure may involve one or more partially folded in‐
termediate states (Figure 1). It is not surprising that stress induced alterations in the physio‐
logical conditions may change the folding process and give rise to protein misfolding and