Unusual clustering of carboxyl side chains in the core of iron-free ribonucleotide reductase
Article Abstract:
Ribonucleotide reductase, an important enzyme in DNA synthesis, is made up of two dimeric proteins, R1 and R2. Some R2 protein has been found to have a novel structure lacking in iron. The iron-free or apoR2 protein does not change its form because it has a group of four carboxyl side chains in the subunit's interior. This arrangement causes apoR2 to lack the usual placement of charged residues in proteins. The unusual structure derives stability from considerable van der Waals interactions and hydrogen bonds.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1993
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Naturally occurring antibodies devoid of light chains
Article Abstract:
A study conducted to determine the presence of Immunoglobin-G (IgG) like material of Mr 100K in Camel's serum reveals that the combination of Vl and VH repertoires results in a diversity of antibodies. The hypermutation in B cells in germinal centres increases the diversity and affinity of antibodies. These molecules are devoid of light-chains and have a large antigen-binding repertoire formed with heavy-chain dimers. A common feature of all camelids is the heavy-chain IgGs.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1993
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Observation of spin and charge collective modes in one-dimensional metallic chains
Article Abstract:
In the Luttinger liquid formalism, quasiparticles are replaced by collective excitations involving spin and charge, predicting power-law behaviour for the properties of one-dimensional metals. Photoemission data from one-dimensional metal constructed on an insulating substrate is presented. The spectra incorporate structures which indicate the excitation of spin and charge collective modes.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1999
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