1NWK

CRYSTAL STRUCTURE OF MONOMERIC ACTIN IN THE ATP STATE

Summary for 1NWK

• Entry DOI: 10.2210/pdb1nwk/pdb
• Related: 1J6Z
• Descriptor: Actin, alpha skeletal muscle, CALCIUM ION, PHOSPHOAMINOPHOSPHONIC ACID-ADENYLATE ESTER, ... (5 entities in total)
• Functional Keywords: actin, tetramethylrhodamine-5-maleimide, atp-state, amppnp, contractile protein
• Biological source: Oryctolagus cuniculus (rabbit)
• Cellular location: Cytoplasm, cytoskeleton: P68135
• Total number of polymer chains: 1
• Total formula weight: 43025.66

Authors

Graceffa, P.,Dominguez, R. (deposition date: 2003-02-06, release date: 2003-10-14, Last modification date: 2024-04-03)

Primary citation

Graceffa, P.,Dominguez, R.
Crystal structure of monomeric actin in the ATP state. Structural basis of nucleotide-dependent actin dynamics.
J.Biol.Chem., 278:34172-34180, 2003

PubMed Abstract: A nucleotide-dependent conformational change regulates actin filament dynamics. Yet, the structural basis of this mechanism remains controversial. The x-ray crystal structure of tetramethylrhodamine-5-maleimide-actin with bound AMPPNP, a non-hydrolyzable ATP analog, was determined to 1.85-A resolution. A comparison of this structure to that of tetramethylrhodamine-5-maleimide-actin with bound ADP, determined previously under similar conditions, reveals how the release of the nucleotide gamma-phosphate sets in motion a sequence of events leading to a conformational change in subdomain 2. The side chain of Ser-14 in the catalytic site rotates upon Pi release, triggering the rearrangement of the loop containing the methylated His-73, referred to as the sensor loop. This in turn causes a transition in the DNase I-binding loop in subdomain 2 from a disordered loop in ATP-actin to an ordered alpha-helix in ADP-actin. Despite this conformational change, the nucleotide cleft remains closed in ADP-actin, similar to ATP-actin. An analysis of the existing structures of members of the actin superfamily suggests that the cleft is open in the nucleotide-free state.

PubMed: 12813032
DOI: 10.1074/jbc.M303689200

Experimental method

X-RAY DIFFRACTION (1.85 Å)