NMR Analysis of Methyl Groups at 100-500 kDa: Model Systems and Arp2/3 Complex

Journal Article · Tue Jul 01 00:00:00 EDT 2003 · Biochemistry

DOI:https://doi.org/10.1021/bi034536j· OSTI ID:1152352

Kreishman-Deitrick, Mara ^[1]; Egile, Coumaran ^[2]; Hoyt, David W. ^[3]; Ford, Joseph J. ^[3]; Rong, Li ^[2]; Rosen, Michael K. ^[1]

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1. Univ. of Texas, Dallas, TX (United States). Southwestern Medical Center
2. Harvard Medical School, Boston, MA (United States)
3. Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)

Large macromolecular machines are among the most important and challenging targets for structural and mechanistic analyses. Consequently, there is great interest in development of NMR methods for the study of multicomponent systems in the 50-500 kDa range. Biochemical methods also must be developed in concert to produce such systems in selectively labeled form. Here, we present ¹H/¹³C-HSQC spectra of protonated methyl groups in a model system that mimics molecular weights up to ~560 kDa. Signals from side chain methyl groups of Ile, Leu, and Val residues are clearly detectable at correlation times up to ~330 ns. We have also developed a biochemical procedure to produce the 240 kDa, heteroheptameric Arp2/3 actin nucleation complex selectively labeled at one subunit and obtained ¹H/¹³C-HSQC spectra of this assembly. Sensitivity in spectra of both the Arp2/3 complex and the model system indicate that methyl groups will be useful sources of information in nonsymmetric systems with molecular weights greater than 600 kDa at concentrations less than 100 μM. Methyl analyses will complement TROSY and CRINEPT analyses of amides in NMR studies of structure and molecular interactions of extremely large macromolecules and assemblies.

• Research Organization: Environmental Molecular Sciences Laboratory (EMSL), Richland, WA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER)
• OSTI ID: 1152352
• Journal Information: Biochemistry, Vol. 42, Issue 28; ISSN 0006-2960
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English

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