Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 2-mer - A1B1 

Biological assembly 1 assigned by authors and generated by PISA (software)

Biological Assembly Evidence: fluorescence resonance energy transfer

Macromolecule Content

• Total Structure Weight: 71.2 kDa 
• Atom Count: 4,424 
• Modelled Residue Count: 555 
• Deposited Residue Count: 619 
• Unique protein chains: 2

 6OF7

Crystal structure of the CRY1-PER2 complex

• PDB DOI:  https://doi.org/10.2210/pdb6OF7/pdb

• Classification: CIRCADIAN CLOCK PROTEIN
• Organism(s): Mus musculus, Homo sapiens
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2019-03-28 Released: 2020-03-04 
• Deposition Author(s): Michael, A.K., Fribourgh, J.L., Tripathi, S.M., Partch, C.L.
• Funding Organization(s): National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 3.11 Å
• R-Value Free: 0.262 
• R-Value Work: 0.208 
• R-Value Observed: 0.211 

Literature

Dynamics at the serine loop underlie differential affinity of cryptochromes for CLOCK:BMAL1 to control circadian timing.

Fribourgh, J.L., Srivastava, A., Sandate, C.R., Michael, A.K., Hsu, P.L., Rakers, C., Nguyen, L.T., Torgrimson, M.R., Parico, G.C.G., Tripathi, S., Zheng, N., Lander, G.C., Hirota, T., Tama, F., Partch, C.L.

(2020) Elife 9

• PubMed: 32101164 
• DOI: https://doi.org/10.7554/eLife.55275
• Primary Citation of Related Structures:  
  6OF7


• PubMed Abstract: 
  

Mammalian circadian rhythms are generated by a transcription-based feedback loop in which CLOCK:BMAL1 drives transcription of its repressors (PER1/2, CRY1/2), which ultimately interact with CLOCK:BMAL1 to close the feedback loop with ~24 hr periodicity. Here we pinpoint a key difference between CRY1 and CRY2 that underlies their differential strengths as transcriptional repressors. Both cryptochromes bind the BMAL1 transactivation domain similarly to sequester it from coactivators and repress CLOCK:BMAL1 activity. However, we find that CRY1 is recruited with much higher affinity to the PAS domain core of CLOCK:BMAL1, allowing it to serve as a stronger repressor that lengthens circadian period. We discovered a dynamic serine-rich loop adjacent to the secondary pocket in the photolyase homology region (PHR) domain that regulates differential binding of cryptochromes to the PAS domain core of CLOCK:BMAL1. Notably, binding of the co-repressor PER2 remodels the serine loop of CRY2, making it more CRY1-like and enhancing its affinity for CLOCK:BMAL1.

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Organizational Affiliation: 

Center for Circadian Biology, University of California San Diego, La Jolla, United States.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Cryptochrome-1	A	491	Mus musculus	Mutation(s): 0  Gene Names: Cry1
UniProt & NIH Common Fund Data Resources
Find proteins for P97784 (Mus musculus) Explore P97784  Go to UniProtKB:  P97784
IMPC:  MGI:1270841

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
Period circadian protein homolog 2	B	128	Homo sapiens	Mutation(s): 0  Gene Names: PER2, KIAA0347
UniProt & NIH Common Fund Data Resources
Find proteins for O15055 (Homo sapiens) Explore O15055  Go to UniProtKB:  O15055
PHAROS:  O15055

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 3.11 Å
• R-Value Free: 0.262 
• R-Value Work: 0.208 
• R-Value Observed: 0.211 
• Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 72.64	α = 90
b = 81.23	β = 90
c = 98.1	γ = 90

Software Package:

Software Name	Purpose
PHENIX	refinement
MOSFLM	data reduction
Aimless	data scaling
PHASER	phasing

Structure Validation

Entry History & Funding Information

Deposition Data

• Released Date: 2020-03-04 
Deposition Author(s): Michael, A.K., Fribourgh, J.L., Tripathi, S.M., Partch, C.L.

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Funding Organization	Location	Grant Number
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)	United States	GM107069

Revision History  

• Version 1.0: 2020-03-04
  Type: Initial release
  
• Version 1.1: 2020-09-16
  Changes: Database references