Polar and ionizable amino acid residues are frequently found in the transmembrane (TM) regions of membrane proteins. In this study, we show that they help to form extensive hydrogen bond connections between TM helices. We find that almost all TM helices have interhelical hydrogen bonding. In addition, we find that a pair of contacting TM helices is packed tighter when there are interhelical hydrogen bonds between them. We further describe several spatial motifs in the TM regions, including "Polar Clamp" and "Serine Zipper," where conserved Ser residues coincide with tightly packed locations in the TM region. With the examples of halorhodopsin, calcium-transporting ATPase, and bovine cytochrome c oxidase, we discuss the roles of hydrogen bonds in stabilizing helical bundles in polytopic membrane proteins and in protein functions.
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http://dx.doi.org/10.1002/prot.10071 | DOI Listing |
J Am Chem Soc
January 2025
Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, Massachusetts 02139, United States.
The SARS-CoV-2 E protein conducts cations across the cell membrane to cause pathogenicity to infected cells. The high-resolution structures of the E transmembrane domain (ETM) in the closed state at neutral pH and in the open state at acidic pH have been determined. However, the ion conduction mechanism remains elusive.
View Article and Find Full Text PDFInt J Mol Sci
August 2024
Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 9190400, Israel.
An H-bond involves the sharing of a hydrogen atom between an electronegative atom to which it is covalently bound (the donor) and another electronegative atom serving as an acceptor. Such bonds represent a critically important geometrical force in biological macromolecules and, as such, have been characterized extensively. H-bond formation invariably leads to a weakening within the acceptor moiety due to the pulling exerted by the donor hydrogen.
View Article and Find Full Text PDFJ Cell Biochem
November 2023
Bioinformatics Division, ICMR-Regional Medical Research Centre, Bhubaneswar, Odisha, India.
Advances in structural biology have bestowed insights into the pleiotropic effects of neurokinin 1 receptors (NK1R) in diverse patho-physiological processes, thereby highlighting the potential therapeutic value of antagonists directed against NK1R. Herein, we investigate the mode of antagonist recognition to discern the obscure atomic facets germane for the function and molecular determinants of NK1R. To commence discernment of potent antagonists and the conformational changes in NK1R, induced upon antagonist binding, state-of-the-art classical all-atoms molecular dynamics (MD) simulations in lipid mimetic bilayers have been utilized.
View Article and Find Full Text PDFJ Mol Biol
March 2024
Center for Membrane Biology, Department of Biochemistry & Molecular Biology, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX 77030, USA. Electronic address:
Kalium channelrhodopsin 1 from Hyphochytrium catenoides (HcKCR1) is the first discovered natural light-gated ion channel that shows higher selectivity to K than to Na and therefore is used to silence neurons with light (optogenetics). Replacement of the conserved cysteine residue in the transmembrane helix 3 (Cys110) with alanine or threonine results in a >1,000-fold decrease in the channel closing rate. The phenotype of the corresponding mutants in channelrhodopsin 2 is attributed to breaking of a specific interhelical hydrogen bond (the "DC gate").
View Article and Find Full Text PDFJ Pept Sci
February 2024
Department of Chemistry and Biochemistry, University of California, Merced, Merced, CA, USA.
The designability of orthogonal coiled coil (CC) dimers, which draw on well-established design rules, plays a pivotal role in fueling the development of CCs as synthetically versatile assembly-directing motifs for the fabrication of bionanomaterials. Here, we aim to expand the synthetic CC toolkit through establishing a "minimalistic" set of orthogonal, de novo CC peptides that comprise 3.5 heptads in length and a single buried Asn to prescribe dimer formation.
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