In biochemistry, the native state of a protein or

nucleic acid Nucleic acids are biopolymers, macromolecules, essential to all known forms of life. They are composed of nucleotides, which are the monomers made of three components: a 5-carbon sugar, a phosphate group and a nitrogenous base. The two main cl ...

is its properly folded and/or assembled form, which is operative and functional. The native state of a biomolecule may possess all four levels of biomolecular structure, with the secondary through quaternary structure being formed from weak interactions along the covalently-bonded backbone. This is in contrast to the denatured state, in which these weak interactions are disrupted, leading to the loss of these forms of structure and retaining only the biomolecule's primary structure.

Biochemistry

Proteins

While all protein molecules begin as simple unbranched chains of

amino acids Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...

, once completed they assume highly specific three-dimensional shapes. That ultimate shape, known as tertiary structure, is the folded shape that possesses a minimum of free energy. It is a protein's tertiary, folded structure that makes it capable of performing its biological function. In fact, shape changes in proteins are the primary cause of several neurodegenerative diseases, including those caused by

prion Prions are misfolded proteins that have the ability to transmit their misfolded shape onto normal variants of the same protein. They characterize several fatal and transmissible neurodegenerative diseases in humans and many other animals. It ...

s and amyloid (i.e. mad cow disease, kuru, Creutzfeldt–Jakob disease). Many enzymes and other non-structural proteins have more than one native state, and they operate or undergo regulation by transitioning between these states. However, "native state" is used almost exclusively in the singular, typically to distinguish properly folded proteins from denatured or unfolded ones. In other contexts, the folded shape of a protein is most often referred to as its native " conformation" or "structure." Folded and unfolded proteins are often easily distinguished by virtue of their water solubilities, as many proteins become insoluble on denaturation. Proteins in the native state will have defined

secondary structure Protein secondary structure is the three dimensional conformational isomerism, form of ''local segments'' of proteins. The two most common Protein structure#Secondary structure, secondary structural elements are alpha helix, alpha helices and beta ...

, which can be detected spectroscopically, by circular dichroism and by nuclear magnetic resonance (NMR). The native state of a protein can be distinguished from a molten globule, by among other things, distances measured by NMR. Amino acids widely separated in a protein's sequence may touch or lie very close to one another within a stably folded protein. In a molten globule, on the other hand, their time-averaged distances are liable to be greater. Learning ''how'' native state proteins can be manufactured is important, as attempts to create proteins from scratch have resulted in molten globules and not true native state products. Therefore, an understanding of the native state is crucial in

protein engineering Protein engineering is the process of developing useful or valuable proteins. It is a young discipline, with much research taking place into the understanding of protein folding and recognition for protein design principles. It has been used to imp ...

Nucleic acids

Nucleic acids attain their native state through

base pair A base pair (bp) is a fundamental unit of double-stranded nucleic acids consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix and contribute to the folded structure of both DNA ...

ing and, to a lesser extent, other interactions such as

coaxial stacking Nucleic acid tertiary structure is the three-dimensional shape of a nucleic acid polymer. RNA and DNA molecules are capable of diverse functions ranging from molecular recognition to catalysis. Such functions require a precise three-dimensiona ...

. Biological DNA usually exists as long linear

double helices A double is a look-alike or doppelgänger; one person or being that resembles another. Double, The Double or Dubble may also refer to: Film and television * Double (filmmaking), someone who substitutes for the credited actor of a character * ' ...

bound to proteins in chromatin, and biological

RNA Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and deoxyribonucleic acid ( DNA) are nucleic acids. Along with lipids, proteins, and carbohydra ...

such as tRNA often form complex native configurations approaching the complexity of folded proteins. Additionally, artificial nucleic acid structures used in DNA nanotechnology are designed to have specific native configurations in which multiple nucleic acid strands are assembled into a single complex. In some cases native state of biological DNA performs their functions without being controlled by any other regulatory units.

External links

http://www.englandlab.com/protein-folding.html {{DEFAULTSORT:Native State Protein structure