1vhp
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VH-P8, NMR
OverviewOverview
The solution structure of the isolated antibody heavy chain variable, domain (VH)-P8 was determined by NMR spectroscopy. The VH had previously, been modified (camelised) at three positions in its former antibody light, chain variable domain (VL) interface to reduce hydrophobicity by mimicking, camelid heavy chains naturally devoid of light chains. The architecture of, two pleated beta-sheets and the conformation of the H1 and H2 loops in, VH-P8 are very similar to those in non-camelised, VL-associated VH, domains. Major differences concern the H3 loop, which no longer points, towards the now absent VL, and three residues in the former VL interface., The side-chains of Val37 and Trp103 are buried and the Arg38 side-chain, exposed in VH-P8. In non-camelised, VL-associated VH domains the, side-chains of Val37 and Trp103 are in contact with the VL while the Arg38, side-chain is buried within the VH. Reorientation of Trp103 is due to the, local structure in the beta-bulge of strand G. Reorientation of Val37 and, Arg38 is caused by a disruption of regular beta-structure in strand C, opposite the beta-bulge in strand C'. These changes, combined with the, more hydrophilic side-chains of the camelised residues, reduce, hydrophobicity and prevent non-specific binding of camelised VH domains, which proved critical for their use as small recognition units. The VH-P8, structure also indicates structural reasons for two other mutations, specific for light-chain-lacking camel immunoglobins. Absence of the, VH-typical Arg94/Asp101 salt bridge at the base of the H3 loop in VH-P8, may explain why a positively charged residue at position 94 is not, conserved in camels. Reorientation of Val37 suggests a function of the, camel-specific phenylalanine residue at this position in the hydrophobic, core of light-chain-lacking camel heavy chains.
About this StructureAbout this Structure
1VHP is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
Rearrangement of the former VL interface in the solution structure of a camelised, single antibody VH domain., Riechmann L, J Mol Biol. 1996 Jun 28;259(5):957-69. PMID:8683598
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