3MSP

MOTILE MAJOR SPERM PROTEIN (MSP) OF ASCARIS SUUM, NMR, 20 STRUCTURES

Summary for 3MSP

• Entry DOI: 10.2210/pdb3msp/pdb
• NMR Information: BMRB: 4242
• Descriptor: MAJOR SPERM PROTEIN (1 entity in total)
• Functional Keywords: cell motility protein, major sperm protein, amoeboid motility, filaments, polymerization
• Biological source: Ascaris suum (pig roundworm)
• Cellular location: Cell projection, pseudopodium: P27439
• Total number of polymer chains: 2
• Total formula weight: 28556.21

Authors

Haaf, A.,Leclaire III, L.,Roberts, G.,Kent, H.M.,Roberts, T.M.,Stewart, M.,Neuhaus, D. (deposition date: 1998-09-10, release date: 1999-04-20, Last modification date: 2024-05-22)

Primary citation

Haaf, A.,LeClaire 3rd., L.,Roberts, G.,Kent, H.M.,Roberts, T.M.,Stewart, M.,Neuhaus, D.
Solution structure of the motile major sperm protein (MSP) of Ascaris suum - evidence for two manganese binding sites and the possible role of divalent cations in filament formation.
J.Mol.Biol., 284:1611-1624, 1998

PubMed Abstract: The major sperm protein (MSP) of Ascaris suum mediates amoeboid motility by forming an extensive intermeshed system of cytoskeletal filaments analogous to that formed by actin in many other amoeboid cells. MSP is a dimeric molecule that polymerizes to form non-polar filaments constructed from two helical subfilaments that wind round one another. Moreover, MSP filaments can interact with one another to form higher-order assemblies without requiring the range of accessory proteins usually employed in actin-based systems. A knowledge of how MSP polymerizes and forms the hierarchical series of helical MSP macromolecular assemblies is fundamental to understanding locomotion in these cells. Here we describe the solution structure of MSP dimers determined by NMR spectroscopy under conditions where MSP does not polymerize to form filaments. The solution structure is indistinguishable from that observed in putative MSP subfilament helices by X-ray crystallography, indicating that MSP polymerization is not accompanied by a major conformational change. We also show that the rate of MSP polymerization associated with movement of vesicles in an in vitro motility assay is enhanced by the presence of magnesium and manganese ions and use NMR to show that the primary residues that bind these ions are 24-25 and 83-86. These residues are distant from the interface formed between MSP dimers in subfilament helices, and so are probably not involved in this level of polymerization. Instead the manganese and magnesium ion binding appears to be associated with the assembly of subfilaments into filaments and their subsequent aggregation into bundles.

PubMed: 9878374
DOI: 10.1006/jmbi.1998.2291

Experimental method

SOLUTION NMR