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1. Integrated structural model of the palladin–actin complex using XL ‐ MS , docking, NMR , and SAXS

   https://doi.org/10.1002/pro.70122  

   Sargent, Rachel; Liu, David H; Yadav, Rahul; Glennenmeier, Drew; Bradford, Colby; Urbina, Noely; Beck, Moriah R (May 2025, Protein Science)

   Cortajarena, Aitziber L (Ed.)

   Abstract Palladin is an actin‐binding protein that accelerates actin polymerization and is linked to the metastasis of several types of cancer. Previously, three lysine residues in an immunoglobulin‐like domain of palladin have been identified as essential for actin binding. However, it is still unknown where palladin binds to F‐actin. Evidence that palladin binds to the sides of actin filaments to facilitate branching is supported by our previous study showing that palladin was able to compensate for Arp2/3 in the formation ofListeriaactin comet tails. Here, we used chemical crosslinking to covalently link palladin and F‐actin residues based on spatial proximity. Samples were then enzymatically digested, separated by liquid chromatography, and analyzed by tandem mass spectrometry. Peptides containing the crosslinks and specific residues involved were then identified for input to the HADDOCK docking server to model the most likely binding conformation. Small‐angle x‐ray scattering was used to provide further insight into palladin flexibility and the binding interface, and NMR spectra identified potential interactions between palladin's Ig domains. Our final structural model of the F‐actin:palladin complex revealed how palladin interacts with and stabilizes F‐actin at the interface between two actin monomers. Three actin residues that were identified in this study also appear commonly in the actin‐binding interface with other proteins such as myotilin, myosin, and tropomodulin. An accurate structural representation of the complex between palladin and actin extends our understanding of palladin's role in promoting cancer metastasis through the regulation of actin dynamics. 

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2. 2.2.2-Cryptand complexes of neptunium( iii ) and plutonium( iii )

   https://doi.org/10.1039/D1CC05904A  

   Goodwin, Conrad A.; Ciccone, Sierra R.; Bekoe, Samuel; Majumdar, Sourav; Scott, Brian L.; Ziller, Joseph W.; Gaunt, Andrew J.; Furche, Filipp; Evans, William J. (January 2022, Chemical Communications)

   New coordination environments are reported for Np( iii ) and Pu( iii ) based on pilot studies of U( iii ) in 2.2.2-cryptand (crypt). The U( iii )-in-crypt complex, [U(crypt)I 2 ][I], obtained from the reaction between UI 3 and crypt, is treated with Me 3 SiOTf (OTf = O 3 SCF 3 ) in benzene to form the [U(crypt)(OTf) 2 ][OTf] complex. Similarly, the isomorphous Np( iii ) and Pu( iii ) complexes were obtained similarly starting from [AnI 3 (THF) 4 ]. All three complexes (1-An; An = U, Np, Pu) contain an encapsulated actinide in a THF-soluble complex. Absorption spectroscopy and DFT calculations are consistent with 5f 3 U( iii ), 5f 4 Np( iii ), and 5f 5 Pu( iii ) electron configurations. 

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3. L eg M uscle A rchitecture in P rimates and I ts C orrelation with L ocomotion P atterns

   https://doi.org/10.1002/ar.23745  

   Marchi, Damiano; Leischner, Carissa L; Pastor, Francisco; Hartstone‐Rose, Adam (March 2018, The Anatomical Record)

   ABSTRACT Bone biomechanical studies indicate that leg bone structure can be related to different locomotor patterns. The osteological correlates of extant primates’ locomotion patterns and substrate use are important to consider when estimating corresponding behaviors of extinct primates. Here, we test if these same patterns are seen in the differences in leg muscular architecture. Muscle mass, fascicle lengths (FL), physiological cross‐sectional area (PCSA), reduced PCSA (RPCSA) and tendon‐to‐muscle belly ratio were studied in 33 primate species (6 strepsirrhines, 14 platyrrhines and 13 catarrhines). Muscles were grouped into toe and ankle flexors and extensors and studied for phylogenetic and functional signals. All variables strongly correlate with body mass: strength variables (mass, PCSA and RPCSA) scale with positive allometry, whereas the speed/stretch measure (FL) trend toward negative allometry. Thus, larger primates are relatively stronger than smaller species, but they have relatively shorter leg muscle fibers than smaller primates. The strongest functional signal emerged when comparing belly‐muscle tendon unit (MTU) length ratio in leaping and non‐leaping primates. Leapers show significantly smaller plantarflexor belly‐MTU ratio. Surprisingly, no significant results reflect a correlation between muscle architecture and substrate and locomotor groups. However, several trends suggest that a larger sample and more fine‐grained defined categories could produce significant results. These results show the complex relation between leg bone biomechanics and muscle architecture and demand for further studies on this topic. Anat Rec, 301:515–527, 2018. © 2018 Wiley Periodicals, Inc. 

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4. Metal–ligand and hydrogen bonding in the active site of Fe( iii )-, Mn( iii )- and Co( iii )-myoglobins

   https://doi.org/10.1039/D4DT03246B  

   Freindorf, Marek; Kraka, Elfi (March 2025, Dalton Transactions)

   We investigated in this work strength of metal–ligand and hydrogen bonding in complexes formed between Fe, Mn, and Co myoglobin and molecular ligands such as methanol, water, nitrite, and azide involving ε and δ protonation forms of distal histidine. 

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5. The femora of Drepanosauromorpha ( Reptilia : Diapsida ): Implications for the functional evolution of the thigh of Sauropsida

   https://doi.org/10.1002/ar.25160  

   Pritchard, Adam C.; Irmis, Randall B.; Olori, Jennifer C.; Nesbitt, Sterling J.; Smith, Nathan D.; Stocker, Michelle R.; Turner, Alan H. (February 2023, The Anatomical Record)

   The femora of diapsids have undergone morphological changes related to shifts in postural and locomotor modes, such as the transition from plesiomorphic amniote and diapsid taxa to the apomorphic conditions related to a more erect posture within Archosauriformes. One remarkable clade of Triassic diapsids is the chameleon-like Drepanosauromorpha. This group is known from numerous articulated but heavily compressed skeletons that have the potential to further inform early reptile femoral evolution. For the first time, we describe the three-dimensional osteology of the femora of Drepanosauromorpha, based on undistorted fossils from the Upper Triassic Chinle Formation and Dockum Group of North America. We identify apomorphies and a combination of character states that link these femora to those in crushed specimens of drepanosauromorphs and compare our sample with a range of amniote taxa. Several characteristics of drepanosauromorph femora, including a hemispherical proximal articular surface, prominent asymmetry in the proximodistal length of the tibial condyles, and a deep intercondylar sulcus, are plesiomorphies shared with early diapsids. The femora contrast with those of most diapsids in lacking a crest-like, distally tapering internal trochanter. They bear a ventrolaterally positioned tuberosity on the femoral shaft, resembling the fourth trochanter in Archosauriformes. The reduction of an internal trochanter parallels independent reductions in therapsids and archosauriforms. The presence of a ventrolaterally positioned trochanter is also similar to that of chameleonid squamates. Collectively, these features demonstrate a unique femoral morphology for drepanosauromorphs, and suggest an increased capacity for femoral adduction and protraction relative to most other Permo-Triassic diapsids. 

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