IQ calmodulin-binding motif

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IQ calmodulin-binding motif
PDB 1wdc EBI.jpg
Structure of the regulatory domain of scallop myosin at 2 A resolution. [1]
Identifiers
SymbolIQ
Pfam PF00612
InterPro IPR000048
SMART SM00015
PROSITE PS50096
SCOP2 1wdc / SCOPe / SUPFAM
Available protein structures:
Pfam   structures / ECOD  
PDB RCSB PDB; PDBe; PDBj
PDBsum structure summary
PDB 1b7t , 1br1 , 1br2 , 1br4 , 1d0x , 1d0y , 1d0z , 1d1a , 1d1b , 1d1c , 1dfk , 1dfl , 1fmv , 1fmw , 1jwy , 1jx2 , 1kk7 , 1kk8 , 1kqm , 1kwo , 1l2o , 1lkx , 1lvk , 1mma , 1mmd , 1mmg , 1mmn , 1mnd , 1mne , 1oe9 , 1qvi , 1s5g , 1scm , 1sr6 , 1vom , 1w7i , 1w7j , 1wdc , 2mys

The IQ calmodulin-binding motif is an amino acid sequence motif containing the following sequence:

Contents

The term "IQ" refers to the first two amino acids of the motif: isoleucine (commonly) and glutamine (invariably).

Function

Calmodulin (CaM) is recognized as a major calcium (Ca2+) sensor and orchestrator of regulatory events through its interaction with a diverse group of cellular proteins. Three classes of recognition motifs exist for many of the known CaM binding proteins; the IQ motif as a consensus for Ca2+-independent binding and two related motifs for Ca2+-dependent binding, termed 1-14 and 1-5-10 based on the position of conserved hydrophobic residues. [2]

Example

The regulatory domain of scallop myosin is a three-chain protein complex that switches on this motor in response to Ca2+ binding. Side-chain interactions link the two light chains in tandem to adjacent segments of the heavy chain bearing the IQ-sequence motif. The Ca2+-binding site is a novel EF hand motif on the essential light chain and is stabilized by linkages involving the heavy chain and both light chains, accounting for the requirement of all three chains for Ca2+binding and regulation in the intact myosin molecule. [3]

Related Research Articles

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<span class="mw-page-title-main">MYLK2</span> Protein-coding gene in the species Homo sapiens

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<span class="mw-page-title-main">WRKY protein domain</span> Protein domain

The WRKY domain is found in the WRKY transcription factor family, a class of transcription factors. The WRKY domain is found almost exclusively in plants although WRKY genes appear present in some diplomonads, social amoebae and other amoebozoa, and fungi incertae sedis. They appear absent in other non-plant species. WRKY transcription factors have been a significant area of plant research for the past 20 years. The WRKY DNA-binding domain recognizes the W-box (T)TGAC(C/T) cis-regulatory element.

<span class="mw-page-title-main">LRRIQ3</span> Protein-coding gene in the species Homo sapiens

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References

  1. Houdusse A, Cohen C (January 1996). "Structure of the regulatory domain of scallop myosin at 2 A resolution: implications for regulation". Structure. 4 (1): 21–32. doi: 10.1016/S0969-2126(96)00006-8 . PMID   8805510.
  2. Rhoads AR, Friedberg F (April 1997). "Sequence motifs for calmodulin recognition". FASEB J. 11 (5): 331–40. doi: 10.1096/fasebj.11.5.9141499 . PMID   9141499. S2CID   1877645.
  3. Xie X, Harrison DH, Schlichting I, Sweet RM, Kalabokis VN, Szent-Györgyi AG, Cohen C (March 1994). "Structure of the regulatory domain of scallop myosin at 2.8 A resolution". Nature. 368 (6469): 306–12. Bibcode:1994Natur.368..306X. doi:10.1038/368306a0. PMID   8127365. S2CID   4279198.
This article incorporates text from the public domain Pfam and InterPro: IPR000048