Photosynthetic Protein Complexes

Perfectly timed, this handbook covers many important aspects of the topic that have only recently been understood -- making this a truly comprehensive work. With its extensive use of color, it surveys the most important proteins involved in photosynthesis, discussing the structural information we have at our disposal. Most chapters are dedicated to one protein, while a few also summarize general associated concepts. The book also has an accompanying website that contains data files and animations to allow readers to visualize many of the complicated proteins presented. A must for anyone studying photosynthesis and structural biology, as well as those working in the plant and crop biotechnology industry.

This book chronicles a few approaches to constructing biohybrid devices using photosynthetic protein complexes. Can the abundantly available solar energy be tapped to meet our rising energy demands using green and cheap active materials? Exploring nature’s own tiny solar factories, the photosynthetic proteins could hold the key. Photosynthetic pigment-protein complexes found in plants and certain types of bacteria transduce sunlight into biologically useful forms of energy through a photochemical charge separation that has a 100% quantum efficiency. Getting the photoproteins to perform this efficient energy conversion reaction in a semi-artificial setup is central to developing biohybrid solar technologies, a promising green alternative to today’s photovoltaics. This book looks into the existing challenges and opportunities in the field of biohybrid photovoltaics and provides a few prospective methods of enhancing the photocurrent and photovoltage in these devices. The book targets the readership of students, academics, and industrial practitioners who are interested in alternative solar technologies.

Photosystem II is a 700-kDa membrane-protein super-complex responsible for the light-driven splitting of water in oxygenic photosynthesis. The photosystem is comprised of two 350-kDa complexes each made of 20 different polypeptides and over 80 co-factors. While there have been major advances in understanding the mature structure of this photosystem many key protein factors involved in the assembly of the complex do not appear in the holoenzyme. The mechanism for assembling this super-complex is a very active area of research with newly discovered assembly factors and subcomplexes requiring characterization. Additionally the ability to split water is inseparable from light-induced photodamage that arises from radicals and reactive O2 species generated by Photosystem II chemistry. Consequently, to sustain water splitting, a “self repair” cycle has evolved whereby damaged protein is removed and replaced so as to extend the working life of the complex. Understanding how the biogenesis and repair processes are coordinated is among several important questions that remain to be answered. Other questions include: how and when are the inorganic cofactors inserted during the assembly and repair processes and how are the subcomplexes protected from photodamage during assembly? Evidence has also been obtained for Photosystem II biogenesis centers in cyanobacteria but do these also exist in plants? Do the molecular mechanisms associated with Photosystem II assembly shed fresh light on the assembly of other major energy-transducing complexes such as Photosystem I or the cytochrome b6/f complex or indeed other respiratory complexes? The contributions to this Frontiers in Plant Science Research Topic are likely to reveal new details applicable to the assembly of a range of membrane-protein complexes, including aspects of self-assembly and solar energy conversion that may be applied to artificial photosynthetic systems. In addition, a deeper understanding of Photosystem II assembly — particularly in response to changing environmental conditions — will provide new knowledge underpinning photosynthetic yields which may contribute to improved food production and long-term food security.

To perform photosynthesis, plants, algae and bacteria possess well organized and closely coupled photosynthetic pigment-protein complexes. The information on energy transfer processes and protein dynamics contained in the narrow zero-phonon lines at low temperatures is hidden under the inhomogeneous broadening. Thus, it is difficult to analyze the spectroscopic properties of these complexes in sufficient detail by conventional spectroscopy methods. In this context, high resolution spectroscopy techniques such as Spectral Hole Burning, Fluorescence Line Narrowing and Single Molecule / Single Complex Spectroscopy are powerful tools designed to overcome the inhomogeneous broadening difficulty. This thesis focuses mainly on the low-temperature protein dynamics of several photosynthetic protein complexes (LH2, CP43, CP29 and LHCII). The hole growth kinetics and the shape of the anti-hole due to the non-photochemical spectral hole burning have been explored, and interpreted within the framework of theoretical models describing spectral diffusion due to conformational changes between nearly identical substates on a multi-tier protein energy landscapes.

Pigment-Protein Complexes in Plastids: Synthesis and Assembly covers the different aspects of biosynthesis, assembly, and function of pigment-protein complexes. This book focuses on the molecular biology and physiological relevance of chlorophyll-protein complexes. The regulation and biosynthesis of chlorophyll proteins that involve a coordinated expression of nuclear and plastid genes and require communication among the cell organelles to respond properly to changing light and temperature conditions are also deliberated. This publication is intended for researchers in the fields of plant molecular biology, genetics, plant physiology and biochemistry, and cell biology, as well as students and teachers in agriculture, horticulture, biology, and biochemistry interested in pigment-protein complexes.

Biotechnological Applications of Photosynthetic Proteins: Biochips, Biosensors and Biodevices provides an overview of the recent photosystem II research and the systems available for the bioassay of pollutants using biosensors that are based on the photochemical activity. The data presented in this book serves as a basis for the development of a commercial biosensor for use in rapid pre-screening analyses of photosystem II pollutants, minimising costly and time-consuming laboratory analyses.