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.

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.

Ever since the discovery of the photoelectric effect, researchers have been trying to improve the efficiency of converting sunlight into electricity through photovoltaic devices. Photosynthetic organisms provide clues for harvesting sunlight and storing the energy in chemical forms. This book offers a concise overview of the fundamental concepts of photosynthesis and the emerging photovoltaic technologies, casting light on the symbiotic relation between these spheres of science. Although there are many books about the fundamentals of photosynthesis and the various aspects of the photosynthetic processes, this is the first volume to focus on the prospects of studying the photosynthetic proteins, understanding and applying their properties to design prospective solar energy conversion devices that are sustainable and efficient. All in all, the book aims to bring together the present know-how on organic photovoltaics and dye-sensitized solar cells with that of the emerging bio-photovoltaics and the underlying physics of photosynthesis to foster a more eclectic research that would converge towards a sustainable energy technology for the future. The book mainly serves as a bridge to connect biochemists, who study photosynthetic proteins, and physicists and engineers who design and develop photovoltaic devices. Scientists, engineers and students in the fields of photosynthetic research and solar energy research can use this book as a ready reference. Key selling features: Covers both methods and bio-based materials needed to build bio-based photovoltaics Focuses on both techniques and applications Summarizes the advantages and limitations of various techniques Contributors from multiple disciplines integrate the knowledge of photosynthetic proteins and the physics/engineering of photovoltaic devices. Includes adaptive designs and techniques used in other types of solar cells to for the design of protein-based PVs

Excitons are considered as the basic concept used by describing the spectral properties of photosynthetic pigment-protein complexes and excitation dynamics in photosynthetic light-harvesting antenna and reaction centers. Following the recently obtained structures of a variety of photosynthetic pigment-protein complexes from plants and bacteria our interest in understanding the relation between structure, function and spectroscopy has strongly increased. These data demonstrate a short interpigment distance (of the order of 1 nm or even smaller) and/or a highly symmetric (ring-like) arrangement of pigment molecules in peripheral light-harvesting complexes of photosynthetic bacteria. Books which were devoted to the exciton problem so far mainly considered the spectral properties of molecular crystals. However, the small size of these pigment aggregates in the pigment-protein complexes as well as the role of the protein, which is responsible for the structural arrangement of the complex, clearly will have a dramatic influence on the pigment spectra and exciton dynamics. All these aspects of the problem are considered in this book. Exciton theory is mainly considered for small molecular aggregates (dimers, ring-like structures etc.). Together with the theoretical description of the classical conceptual approach, which mainly deals with polarization properties of the absorption and fluorescence spectra, the nonlinear femtosecond spectroscopy which is widely used for investigations now is also discussed. A large part of the book demonstrates the excitonic effects in a multitude of photosynthetic pigment-protein complexes and how we can understand these properties on the basis of the exciton concept.