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Transition metal amino acid complexes are a large family of coordination complexes containing the conjugate bases of the amino acids, the 2-aminocarboxylates. Amino acids are prevalent in nature, and all of them function as ligands toward the transition metals. [1] Not included in this article are complexes of the amides (including peptide) and ...
The presence of the metal ion allows metalloenzymes to perform functions such as redox reactions that cannot easily be performed by the limited set of functional groups found in amino acids. [16] The iron atom in most cytochromes is contained in a heme group. The differences between those cytochromes lies in the different side-chains.
Ligands such as DTPA, which have eight donor atoms are used to form complexes with large metal ions such as lanthanide or actinide ions which usually form 8- or 9-coordinate complexes. 5-membered and 6-membered chelate rings give the most stable complexes. 4-membered rings are subject to internal strain because of the small inter-bond angle is ...
The N-O distance required is less than 4 Å (400 pm). Amino acids greater than this distance apart do not qualify as forming a salt bridge. [11] Due to the numerous ionizable side chains of amino acids found throughout a protein, the pH at which a protein is placed is crucial to its stability.
Proteins form by amino acids undergoing condensation reactions, in which the amino acids lose one water molecule per reaction in order to attach to one another with a peptide bond. By convention, a chain under 30 amino acids is often identified as a peptide, rather than a protein. [1]
Binding of metal ions via chelation is usually achieved via histidines or cysteines. In some cases this is a necessary part of their folding and maintenance of a tertiary structure. Alternatively, a metal-binding protein may maintain its structure without the metal (apo form) and bind it as a ligand (e.g. as part of metal homeostasis).
The proposal that proteins were linear chains of α-amino acids was made nearly simultaneously by two scientists at the same conference in 1902, the 74th meeting of the Society of German Scientists and Physicians, held in Karlsbad. Franz Hofmeister made the proposal in the morning, based on his observations of the biuret reaction in proteins.
The alpha helix is also commonly called a: Pauling–Corey–Branson α-helix (from the names of three scientists who described its structure); 3.6 13-helix because there are 3.6 amino acids in one ring, with 13 atoms being involved in the ring formed by the hydrogen bond (starting with amidic hydrogen and ending with carbonyl oxygen)