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Short-range and long-range contacts are important in forming protein structure. The proteins can be grouped into four different structural classes according to the content and topology of alpha-helices and beta-strands, and there are all-alpha, all-beta, alpha/beta and alpha+beta proteins. However, there is much difference in statistical property for those classes of proteins. In this paper, we will discuss protein structure in the view of the relative number of long-range (short-range) contacts for each residue. We find the percentage of residues having a large number of long-range contacts in protein is small in all-alpha class of proteins, and large in all-beta class of proteins. However, the percentage of residues is almost the same in alpha/beta and alpha+beta classes of proteins. We calculate the percentage of residues having the number of long-range contacts greater than or equal to (>/=) N(L)=5, and 7 for 428 proteins. The average percentage is 13.3%, 54.8%, 41.4% and 37.0% for all-alpha, all-beta, alpha/beta and alpha+beta classes of proteins with N(L)=5, respectively. With N(L) increasing, the percentage decreases, especially for all-alpha class of proteins. In the meantime, the percentage of residues having the number of short-range contacts greater than or equal to N(S) (>/=N(S)) in protein samples is large for all-alpha class of proteins, and small for all-beta class of proteins, especially for large N(S). We also investigate the ability of amino residues in forming a large number of long-range and short-range contacts. Cys, Val, Ile, Tyr, Trp and Phe can form a large number of long-range contacts easily, and Glu, Lys, Asp, Gln, Arg and Asn can form a large number of long-range contacts, but with difficulty. We also discuss the relative ability in forming short-range contacts for 20 amino residues. Comparison with Fauchere-Pliska hydrophobicity scale and the percentage of residues having large number of long-range contacts is also made. This investigation can provide some insights into the protein structure.
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http://dx.doi.org/10.1016/s0301-4622(03)00033-4 | DOI Listing |
Genes Immun
September 2025
Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, USA.
Double-strand breaks represent the most dangerous form of DNA damage, and in resting cells, these breaks are sealed via the non-homologous end joining (NHEJ) factor Ligase IV (LIG4). Excessive NHEJ may be genotoxic, necessitating multiple mechanisms to control NHEJ activity. However, a clear mechanism of transcriptional control for them has not yet been identified.
View Article and Find Full Text PDFPLoS One
September 2025
Grupo Interdisciplinario de Biología Teórica, Instituto de Neurociencia Cognitiva y Traslacional (INCyT), Universidad Favaloro, INECO, CONICET, Buenos Aires, Argentina.
The present paper analyzes the sounds emitted by pre-hatching chicks, focusing on those named as "clicks," which are thought to mediate pre-hatching social interactions and hatching synchronization. Representative acoustic signals were analyzed under three incubation conditions: (1) isolated pre-hatching chicks (n = 13), (2) pre-hatching chicks in contact with others of the same age (n = 14), and (3) pre-hatching chicks in contact with other of different age (n = 10 for each group: leader and follower). Customized MATLAB software was developed to (a) identify and isolate clicks from other recorded sounds, (b) represent them as temporal series of stochastic point processes, and (c) determine whether click emission dynamics resembled white noise or exhibited characteristics of informative signals.
View Article and Find Full Text PDFbioRxiv
August 2025
Plant Epigenomics, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, 85354, Germany.
Scalable proxies of 3D genome interactions, such as from single-cell co-accessibility or Deep Learning, systematically overestimate long-range chromatin contacts. To correct this bias, we introduce a penalty function grounded in polymer physics, derived by fitting a multi-component power-law model to experimental Hi-C data from maize, rice, and soybean. This correction substantially improves concordance with Hi-C, reduces false-positive rates of long-range interactions by up to 95%, and reveals distinct decay exponents corresponding to different scales of chromatin organization.
View Article and Find Full Text PDFInsects
August 2025
Facultad de Ciencias Agronómicas, Universidad de Chile, Santiago 8820808, Chile.
The pre-courtship behavior of on trees was recorded for the first time, documenting a putative female "calling" behavior and the consequent male "oriented search," enabling the description of behavioral units, sequences, frequencies, and degrees of stereotypy. Post-resting activity in both sexes began with walking and grooming during the first hour of the scotophase, following a period of daytime inactivity. Subsequently, females extended their ovipositor both horizontally and vertically, alternating between contact with the tree substrate and, simultaneously, walking the surface (=putative calling behavior), while males became active, extending their antennae perpendicularly to the longitudinal body axis.
View Article and Find Full Text PDFInt J Mol Sci
August 2025
Department of Epigenetic Mechanisms of Gene Expression Regulation, Engelhardt Institute of Molecular Biology Russian Academy of Sciences, 119334 Moscow, Russia.
Upon transferal from plastic to Matrigel, melanoma cells demonstrate growth in three dimensions and form de novo vascular networks-known as vasculogenic mimicry-that are characteristic of the stemness phenotype of aggressive tumors. It has been reported that during malignant transformation, stress, or differentiation, the long-range inter-chromosomal interactions between numerous developmental genes and nucleoli are changed. The aim of this work was to study the potential mechanisms behind the development of the vasculogenic mimicry phenotype in melanoma cells and whether the formation of these 3D structures is connected with the reorganization of inter-chromosomal contacts of rDNA clusters.
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