Linked Life Data

21574570

Source:http://linkedlifedata.com/resource/pubmed/id/21574570

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
24
pubmed:dateCreated
2011-6-14
pubmed:abstractText
Mammalian type B (mitochondrial) b(5) cytochromes exhibit greater amino acid sequence diversity than their type A (microsomal) counterparts, as exemplified by the type B proteins from human (hCYB5B) and rat (rCYB5B). The comparison of X-ray crystal structures of hCYB5B and rCYB5B reported herein reveals a striking difference in packing involving the five-strand ?-sheet, which can be attributed to fully buried residue 21 in strand ?4. The greater bulk of Leu21 in hCYB5B in comparison to that of Thr21 in rCYB5B results in a substantial displacement of the first two residues in ?5, and consequent loss of two of the three hydrogen bonds between ?5 and ?4. Hydrogen bonding between the residues is instead mediated by two well-ordered, fully buried water molecules. In a 10 ns molecular dynamics simulation, one of the buried water molecules in the hCYB5B structure exchanged readily with solvent via intermediates having three water molecules sandwiched between ?4 and ?5. When the buried water molecules were removed prior to a second 10 ns simulation, ?4 and ?5 formed persistent hydrogen bonds identical to those in rCYB5B, but the Leu21 side chain was forced to adopt a rarely observed conformation. Despite the apparently greater ease of access of water to the interior of hCYB5B than of rCYB5B suggested by these observations, the two proteins exhibit virtually identical stability, dynamic, and redox properties. The results provide new insight into the factors stabilizing the cytochrome b(5) fold.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
1520-4995
pubmed:author
pubmed:issnType
Electronic
pubmed:day
21
pubmed:volume
50
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5544-54
pubmed:meshHeading
pubmed-meshheading:21574570-Amino Acid Sequence, pubmed-meshheading:21574570-Amino Acid Substitution, pubmed-meshheading:21574570-Animals, pubmed-meshheading:21574570-Carrier Proteins, pubmed-meshheading:21574570-Crystallography, X-Ray, pubmed-meshheading:21574570-Cytochromes b5, pubmed-meshheading:21574570-Enzyme Stability, pubmed-meshheading:21574570-Hemeproteins, pubmed-meshheading:21574570-Humans, pubmed-meshheading:21574570-Hydrogen Bonding, pubmed-meshheading:21574570-Hydrophobic and Hydrophilic Interactions, pubmed-meshheading:21574570-Models, Molecular, pubmed-meshheading:21574570-Molecular Dynamics Simulation, pubmed-meshheading:21574570-Molecular Sequence Data, pubmed-meshheading:21574570-Mutagenesis, Site-Directed, pubmed-meshheading:21574570-Mutation, pubmed-meshheading:21574570-Oxidation-Reduction, pubmed-meshheading:21574570-Protein Interaction Domains and Motifs, pubmed-meshheading:21574570-Protein Structure, Secondary, pubmed-meshheading:21574570-Rats, pubmed-meshheading:21574570-Recombinant Proteins, pubmed-meshheading:21574570-Sequence Homology, Amino Acid, pubmed-meshheading:21574570-Species Specificity, pubmed-meshheading:21574570-Water
pubmed:year
2011
pubmed:articleTitle
Accommodating a nonconservative internal mutation by water-mediated hydrogen bonding between ?-sheet strands: a comparison of human and rat type B (mitochondrial) cytochrome b5.
pubmed:affiliation
Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045, USA.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't