Mismatch, crystallographic

Currently, high-resolution EM image reconstructions for the 26S proteasome (Walz et al. 1998), but no atomic-resolution crystallographic data are available for any complex of 20S proteasomes with ATP-dependent activators. The expected assembly of PAN, the archaebacterial AAA(+) activator of proteasomes (Zwickl et al. 1999) into hexamers suggests a symmetry-mismatched complex in archaebacteria. 

In the case of highly mismatched substrates, such as hexagonal sapphire, cubic GaAs(lll) and Si(lll), there is usually a certain amount of zincblende phase of the nitrides [12,13], separated by crystallographic defects from the wurtzite phase. 

Island growth also occurs with polycrystalline films, but in epitaxy, the islands combine to form a continuous single-crystal film, that is, one with no grain boundaries. In reality, nucleation is much more complex in the case of heteroepitaxy. Nucleation errors may result in relatively large areas, or domains, with different crystallographic orientations. The interfaces between domains are regions of structural mismatch called subgrain boundaries and will be visible in the microstructure. 

The crystal structure of a very short patch repair (Vsr) endonuclease complex with DNA containing a TG mismatch shows novel interactions of intercalated aromatic side chains which recognise the mismatch site. The enzyme also distorts the DNA backbone, and many protein side chain interactions stabilise the complex. Crystallographic studies of duplexes containing the mutagenic... 

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