Protein L consists of a single alpha-helix packed on a four-stranded beta-sheet formed by two symmetrically opposed beta-hairpins. We use a computer-based protein design procedure to stabilize a domain-swapped dimer of protein L in which the second beta-turn straightens and the C-terminal strand inserts into the beta-sheet of the partner. The designed obligate dimer contains three mutations (A52V, N53P, and G55A) and has a dissociation constant of approximately 700 pM, which is comparable to the dissociation constant of many naturally occurring protein dimers. The structure of the dimer has been determined by x-ray crystallography and is close to the in silico model.
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http://dx.doi.org/10.1073/pnas.181354398 | DOI Listing |
Proc Natl Acad Sci U S A
February 2025
SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 16419, Republic of Korea.
The design of organic-peptide hybrids has the potential to combine our vast knowledge of protein design with small molecule engineering to create hybrid structures with complex functions. Here, we describe the computational design of a photoswitchable Ca-binding organic-peptide hybrid. The designed molecule, designated Ca-binding switch (CaBS), combines an EF-hand motif from classical Ca-binding proteins such as calmodulin with a photoswitchable group that can be reversibly isomerized between a spiropyran (SP) and merocyanine (MC) state in response to different wavelengths of light.
View Article and Find Full Text PDFJ Biol Chem
January 2025
T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, 21218, USA. Electronic address:
Truncated hemoglobins (TrHbs) have an ancient origin and are widely distributed in microorganisms where they often serve roles other than dioxygen transport and storage. In extremophiles, these small heme proteins must have features that secure function under challenging conditions: at minimum, they must be folded, retain the heme group, allow substrates to access the heme cavity, and maintain their quaternary structure if present and essential. The genome of the obligate psychropiezophile Shewanella benthica strain KT99 harbors a gene for a TrHb belonging to a little-studied clade of globins (subgroup 2 of group N).
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, NY 14853.
Ammonia oxidizing archaea (AOA) are among the most abundant microorganisms on earth and are known to be a major source of nitrous oxide (NO) emissions, although biochemical origins of this NO remain unknown. Enzymological details of AOA nitrogen metabolism are broadly unavailable. We report the recombinant expression, purification, and characterization of a multicopper oxidase, Nmar_1354, from the AOA .
View Article and Find Full Text PDFNat Commun
January 2025
IGF, Université de Montpellier, CNRS, INSERM, 34094, Montpellier, France.
The metabotropic glutamate receptors (mGlus) are class C G protein-coupled receptors (GPCR) that form obligate dimers activated by the major excitatory neurotransmitter L-glutamate. The architecture of mGlu receptor comprises an extracellular Venus-Fly Trap domain (VFT) connected to the transmembrane domain (7TM) through a Cysteine-Rich Domain (CRD). The binding of L-glutamate in the VFTs and subsequent conformational change results in the signal being transmitted to the 7TM inducing G protein binding and activation.
View Article and Find Full Text PDFElife
January 2025
Department of Molecular and Cell Biology, Berkeley, United States.
Type II nuclear receptors (T2NRs) require heterodimerization with a common partner, the retinoid X receptor (RXR), to bind cognate DNA recognition sites in chromatin. Based on previous biochemical and overexpression studies, binding of T2NRs to chromatin is proposed to be regulated by competition for a limiting pool of the core RXR subunit. However, this mechanism has not yet been tested for endogenous proteins in live cells.
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