A method for the analysis of domain movements in large biomolecular complexes
ABSTRACT A new method for the analysis of domain movements in large, multichain, biomolecular complexes is presented. The method is applicable to any molecule for which two atomic structures are available that represent a conformational change indicating a possible domain movement. The method is blind to atomic bonding and atom type and can, therefore, be applied to biomolecular complexes containing different constituent molecules such as protein, RNA, or DNA. At the heart of the method is the use of blocks located at grid points spanning the whole molecule. The rotation vector for the rotation of atoms from each block between the two conformations is calculated. Treating components of these vectors as coordinates means that each block is associated with a point in a "rotation space" and that blocks with atoms that rotate together, perhaps as part of the same rigid domain, will have colocated points. Thus a domain can be identified from the clustering of points from blocks that span it. Domain pairs are accepted for analysis of their relative movements in terms of screw axes based upon a set of reasonable criteria. Here, we report on the application of the method to biomolecules covering a considerable size range: hemoglobin, liver alcohol dehydrogenase, S-Adenosylhomocysteine hydrolase, aspartate transcarbamylase, and the 70S ribosome. The results provide a depiction of the conformational change within each molecule that is easily understood, giving a perspective that is expected to lead to new insights. Of particular interest is the allosteric mechanism in some of these molecules. Results indicate that common boundaries between subunits and domains are good regions to focus on as movement in one subunit can be transmitted to another subunit through such interfaces.
- SourceAvailable from: Yanbin Zhang
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- "Binding of Mn 2+ ions induced significant conformational changes in both DNA and PaFAN1. When the N-terminal region (NTD and SAP domain) of the metal-free and metalbound structures were superimposed, the overall Ca of the TPR or VRR nuc domains moved by 9° and as much as 7.5 A ˚ (TPR) and 8.0 A ˚ (VRR) toward the NTD (Poornam et al. 2009). The a10 helix serves as a pivot for rotating the C-terminal domains (TPR and VRR nuc) toward the NTDs (and SAP) in the presence of Mn 2+ ions (Fig. 5A,B). "
ABSTRACT: Fanconi anemia (FA) is an autosomal recessive genetic disorder caused by defects in any of 15 FA genes responsible for processing DNA interstrand cross-links (ICLs). The ultimate outcome of the FA pathway is resolution of cross-links, which requires structure-selective nucleases. FA-associated nuclease 1 (FAN1) is believed to be recruited to lesions by a monoubiquitinated FANCI–FANCD2 (ID) complex and participates in ICL repair. Here, we determined the crystal structure of Pseudomonas aeruginosa FAN1 (PaFAN1) lacking the UBZ (ubiquitin-binding zinc) domain in complex with 5′ flap DNA. All four domains of the right-hand-shaped PaFAN1 are involved in DNA recognition, with each domain playing a specific role in bending DNA at the nick. The six-helix bundle that binds the junction connects to the catalytic viral replication and repair (VRR) nuclease (VRR nuc) domain, enabling FAN1 to incise the scissile phosphate a few bases distant from the junction. The six-helix bundle also inhibits the cleavage of intact Holliday junctions. PaFAN1 shares several conserved features with other flap structure-selective nucleases despite structural differences. A clamping motion of the domains around the wedge helix, which acts as a pivot, facilitates nucleolytic cleavage. The PaFAN1 structure provides insights into how archaeal Holliday junction resolvases evolved to incise 5′ flap substrates and how FAN1 integrates with the FA complex to participate in ICL repair.Genes & development 09/2014; 28(28):2276-2290. DOI:10.1101/gad.248492.114 · 12.64 Impact Factor
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- "The rotation angle of the putative membrane interaction loop was calculated using the program Dyndom (Poornam et al., 2009). Due to the limited length of the loop the minimum domain size had to be reduced to 17 residues. "
ABSTRACT: In many vertebrate tissues CD39-like ecto-nucleoside triphosphate diphosphohydrolases (NTPDases) act in concert with ecto-5'-nucleotidase (e5NT, CD73) to convert extracellular ATP to adenosine. Extracellular ATP is a cytotoxic, pro-inflammatory signalling molecule whereas its product adenosine constitutes a universal and potent immune suppressor. Interference with these ectonucleotidases by use of small molecule inhibitors or inhibitory antibodies appears to be an effective strategy to enhance anti-tumour immunity and suppress neoangiogenesis. Here we present the first crystal structures of an NTPDase catalytic ectodomain in complex with the Reactive Blue 2 (RB2)-derived inhibitor PSB-071. In both of the two crystal forms presented the inhibitor binds as a sandwich of two molecules at the nucleoside binding site. One of the molecules is well defined in its orientation. Specific hydrogen bonds are formed between the sulfonyl group and the nucleoside binding loop. The methylphenyl side chain functionality that improved NTPDase2-specificity is sandwiched between R245 and R394, the latter of which is exclusively found in NTPDase2. The second molecule exhibits great in-plane rotational freedom and could not be modelled in a specific orientation. In addition to this structural insight into NTPDase inhibition, the observation of the putative membrane interaction loop (MIL) in two different conformations related by a 10° rotation identifies the MIL as a dynamic section of NTPDases that is potentially involved in regulation of catalysis.Journal of Structural Biology 01/2014; 185(3). DOI:10.1016/j.jsb.2014.01.005 · 3.23 Impact Factor
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- "A ˚ for 476 aligned residues), due to significant relative differences in domain orientation, the most striking of which is the relative position of the C-terminal domain, which requires a rigid body rotation of 41 to produce an optimal superposition (Figure 3A; see Figure S1 available online). Analysis of the domain movements in DynDom (Poornam et al., 2009) indicates that the bending of a single hinge region (residues 454–458), which lies in the linker helix a13, creates this shift in domain position. This region is also responsible for the variability in the relative position of the C-terminal domain of the four chains in the RNase J1 asymmetric unit with motions that are less extensive than that between B. subtilis and T. thermophilus RNase J. "
ABSTRACT: RNase J is an essential enzyme in Bacillus subtilis with unusual dual endonuclease and 5'-to-3' exonuclease activities that play an important role in the maturation and degradation of mRNA. RNase J is also a component of the recently identified "degradosome" of B. subtilis. We report the crystal structure of RNase J1 from B. subtilis to 3.0 Å resolution, analysis of which reveals it to be in an open conformation suitable for binding substrate RNA. RNase J is a member of the β-CASP family of zinc-dependent metallo-β-lactamases. We have exploited this similarity in constructing a model for an RNase J1:RNA complex. Analysis of this model reveals candidate-stacking interactions with conserved aromatic side chains, providing a molecular basis for the observed enzyme activity. Comparisons of the B. subtilis RNase J structure with related enzymes reveal key differences that provide insights into conformational changes during catalysis and the role of the C-terminal domain.Structure 09/2011; 19(9):1241-51. DOI:10.1016/j.str.2011.06.017 · 6.79 Impact Factor