Structural biology is a branch of molecular biology concerned with the study of the architecture and shape of biological macromolecules--proteins and nucleic acids in particular—and what causes them to have the structures they have. This subject is of great interest to biologists, because macromolecules carry out most of the functions of a cell, and because typically it only is by coiling into a specific three-dimensional shape that they are able to perform their functions. This shape, which is called the "tertiary structure" of a molecule, depends in a complicated way on the molecule's basic composition, or "primary structure." Molecular biology is the study of biology at a molecular level. ... A macromolecule is a molecule of high relative molecular mass, the structure of which essentially comprises the multiple repetition of units derived, actually or conceptually, from molecules of low relative molecular mass. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... A nucleic acid is a complex, high-molecular-weight biochemical macromolecule composed of nucleotide chains that convey genetic information. ... Cells in culture, stained for keratin (red) and DNA (green) The cell is the structural and functional unit of all living organisms, sometimes called the building blocks of life. ... In biochemistry, the tertiary structure of a protein is its overall shape. ... A protein primary structure is a chain of amino acids. ...

Biomolecules are too small to see in detail even with the most advanced light microscopes. The methods that structural biologists use to determine their structures generally involving measurements on vast numbers of identical molecules at the same time. These methods include crystallography, NMR, Ultra fast Laser Spectroscopy, Electron Microscopy, Cyrogenic-Electron Microscopy (Cryo-EM), and circular dichroism. Most often researchers use them to study the static "native states" of macromolecules. But variations on these methods are also used to watch nascent or denatured molecules assume or reassume their native states (see e.g. protein folding). A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... 1852 microscope Compound microscope made by John Cuff in 1750 A microscope (Greek: micron = small and scopos = aim) is an instrument for viewing objects that are too small to be seen by the naked or unaided eye. ... Crystallography (from the Greek words crystallon = cold drop / frozen drop, with its meaning extending to all solids with some degree of transparency, and graphein = write) is the experimental science of determining the arrangement of atoms in solids. ... Pacific Northwest National Laboratorys high magnetic field (800 MHz) NMR spectrometer being loaded with sample. ... The electron microscope is a microscope that can magnify very small details with high resolving power due to the use of electrons rather than light to scatter off material, magnifying at levels up to 500,000 times. ... Circular dichroism, or CD, is defined as the differential absorption of left and right hand circularly polarized light. ... In biochemistry, the native state of a protein is its operative or functional form. ... Denaturation is a structural change in biomolecules such as nucleic acids and proteins, usually caused by heat, acids, bases, detergents, or certain chemicals such as urea. ... Protein folding is the process by which a protein assumes its functional shape or conformation. ...

A third approach that structural biologists take to understanding structure is bioinformatics to look for patterns among the diverse sequences that give rise to particular shapes. Researchers often can deduce aspects of the structure of integral membrane proteins based on the membrane topology predicted by hydrophobicity analysis. See: protein structure prediction. Bioinformatics or computational biology is the use of techniques from applied mathematics, informatics, statistics, and computer science to solve biological problems. ... A DNA sequence (sometimes genetic sequence) is a succession of letters representing the primary structure of a real or hypothetical DNA molecule or strand, The possible letters are A, C, G, and T, representing the four nucleotide subunits of a DNA strand (adenine, cytosine, guanine, thymine), and typically these are... Integral membrane protein of the transmembrane type An Integral Membrane Protein (IMP) is a protein molecule (or assembly of proteins) that in most cases spans the biological membrane with which it is associated (especially the plasma membrane) or which, in any case, is sufficiently embedded in the membrane to remain... In biochemistry, the membrane topology of an transmembrane protein describes which portions of the amino-acid sequence of the protein lie within the plane of the surrounding lipid bilayer and which portions protrude into the watery environment on either side. ... The Wikipedia community consider the subject of this article to the encyclopedia. ... Protein structure prediction is one of the most significant tasks tackled in computational structural biology. ...

See also: primary structure, secondary structure, tertiary structure, quaternary structure, structural domain, structural motif, protein subunit, cooperativity, chaperonin, structural genomics, Important publications in structural biology A protein primary structure is a chain of amino acids. ... A representation of the 3D structure of the Myoglobin protein. ... In biochemistry, the tertiary structure of a protein is its overall shape. ... In biochemistry, many proteins are actually assemblies of more than one protein molecule, which in the context of the larger assemblage are known as protein subunits. ... Within a protein, a structural domain (domain) is an element of overall structure that is self-stabilizing and often folds independently of the rest of the protein chain. ... In an unbranched, chain-like biological molecule, such as a protein or a strand of RNA, a structural motif is a three-dimensional structural element or fold within the chain, which appears also in a variety of other molecules. ... In structural biology, a protein subunit or subunit protein is a single protein molecule that assembles (or coassembles) with other protein molecules to form a multimeric or oligomeric protein. ... Cooperativity is a phenomenon in biology displayed by enzymes or receptors that have multiple binding sites. ... GroEL is a protein chaperone required for the proper folding of many proteins in prokaryotes. ... Structural genomics or structural bioinformatics refers to the analysis of macromolecular structure particularly proteins, using computational tools and theoretical frameworks. ... // Aerobiology Anatomy Grays Anatomy Arachnology Astrobiology Biochemistry Bionics Biogeography Bioinformatics Biomechanics Biophysics Botany Cell biology Molecular Biology of the Cell Alberts, Bruce; Johnson, Alexander; Lewis, Julian; Raff, Martin; Roberts, Keith; Walter, Peter New York, Garland Publishing 1983-2002 Description: . This is a must-have introduction to cell biology, suitable...

External links

• Nature: Structural & Molecular Biology magazine website
• Structural Biology - The Virtual Library of Biochemistry and Cell Biology