Myoglobin structure and function: A multiweek biochemistry laboratory project

The invasiveness of robot-assisted total hip replacement is similar to that of conventional surgery

Robot-assisted total hip arthroplasty (R-THA) is increasingly being performed throughout the world. The invasiveness of this operation is unknown. We retrospectively reviewed the cohort of consecutive osteonecrosis of the femoral head (ONFH) patients who received primary R-THA or manual THA (M-THA) from January 2020 to January 2022 in our institution. One experienced surgeon performed all procedures. We calculated the propensity score to match similar patients in different groups by multivariate logistic regression analysis for each patient. We included confounders consisting of age, sex, body mass index (BMI), and operation time. Preoperative serum markers and Harris hip scores (HHS), postoperative serum markers at first day and third day, complications rate, postoperative HHS and Forgotten Joint Score (FJS) at 6 months after surgery of different cohorts were compared. We analyzed 218 ONFH patients treated with THA (98 R-THA patients, and 120 M-THA patients). After propensity score matching, we generated cohorts of 95 patients in R-THA and M-THA groups. We found no significant difference in preoperative serum markers and HHS. In the R-THA cohort, the PLT count was significantly lower on the postoperative day 1 (192.36 ± 41.72 × 109/L Vs 210.47 ± 72.85 × 109/L, p < 0.05). The Hb level was significantly lower on the postoperative third day in the R-THA cohort (98.52 ± 12.99 g/L Vs 104.74 ± 13.15 g/L, p < 0.05). There was no significant difference in the other serum markers between the cohorts on postoperative day 1 and 3 (p > 0.05). The FJS was significantly higher in the R-THA than M-THA group (p = 0.01). There was no significant difference in the postoperative HHS or complication rate between the groups (p > 0.05). The R-THA is not associated with a serious invasiveness compared to M-THA. Patients who underwent R-THA had a better early function compared to those who underwent M-THA.

Serum biomarkers for the assessment of muscle damage in various surgical approaches in primary total hip arthroplasty: a systematic review of comparative studies

PURPOSE

Using serum biomarkers, this systematic review assessed soft tissue injury following different total hip arthroplasty surgical approaches. The purposes were to determine if there is any advantage between the standard and minimal invasive approaches, and to compare tissue damage of the respective surgical approaches using biomarkers such as creatine kinase, myoglobin, c-reactive protein, erythrocyte sedimentation rate, skeletal troponin and interleukins.

METHOD

A search in Pubmed/MEDLINE, Scopus and Web of Science databases was conducted in October 2021 with the use of PRISMA guidelines. Search items were ("biomarkers" OR "markers" OR "tissue damage" OR "muscle damage") AND "approach" AND ("total hip arthroplasty" OR "total hip replacement"). Inclusion criteria were prospective, randomized, controlled trials or prospective, comparative studies, comparing serum markers for muscle damage in two or more surgical approaches for primary total hip arthroplasty. Exclusion criteria were study protocols, case reports, systematic reviews, meta-analyses, studies in non-English language or without available full text, and studies not recording biomarkers of muscle damage.

RESULTS

Initial search revealed 508 studies; after subtraction of duplicates, and exclusion criteria, 31 studies remained for analysis. No advantage between different approaches was found when evaluating biomarkers, and no specific biomarkers had a distinct role in tissue damage in total hip arthroplasty. Anterior and minimally invasive approaches were associated with lower values of soft tissue (creatine kinase) and inflammation (c-reactive protein) biomarkers compared to the standard approaches.

CONCLUSION

Measurement of serum biomarkers after primary total hip arthroplasty for the estimation of tissue damage has unclear or little clinical value.

TRIAL REGISTRATION

PROSPERO Registration: CRD42022303959.

Heme Protein Binding of Sulfonamide Compounds: A Correlation Study by Spectroscopic, Calorimetric, and Computational Methods

Protein-ligand interaction studies are useful to determine the molecular mechanism of the binding phenomenon, leading to the establishment of the structure-function relationship. Here, we report the binding of well-known antibiotic sulfonamide drugs (sulfamethazine, SMZ; and sulfadiazine, SDZ) with heme protein myoglobin (Mb) using spectroscopic, calorimetric, ζ potential, and computational methods. Formation of a 1:1 complex between the ligand and Mb through well-defined equilibrium was observed. The binding constants obtained between Mb and SMZ/SDZ drugs were on the order of 10⁴ M^-1. SMZ with two additional methyl (-CH₃) substitutions has higher affinity than SDZ. Upon drug binding, a notable loss in the helicity (via circular dichroism) and perturbation of the three-dimensional (3D) protein structure (via infrared and synchronous fluorescence experiments) were observed. The binding also indicated the dominance of non-polyelectrolytic forces between the amino acid residues of the protein and the drugs. The ligand-protein binding distance signified high probability of energy transfer between them. Destabilization of the protein structure upon binding was evident from differential scanning calorimetry results and ζ potential analyses. Molecular docking presented the best probable binding sites of the drugs inside protein pockets. Thus, the present study explores the potential binding characteristics of two sulfonamide drugs (with different substitutions) with myoglobin, correlating the structural and energetic aspects.

PDB-101: Educational resources supporting molecular explorations through biology and medicine

The Protein Data Bank (PDB) archive is a rich source of information in the form of atomic-level three-dimensional (3D) structures of biomolecules experimentally determined using macromolecular crystallography, nuclear magnetic resonance (NMR) spectroscopy, and electron microscopy (3DEM). Originally established in 1971 as a resource for protein crystallographers to freely exchange data, today PDB data drive research and education across scientific disciplines. In 2011, the online portal PDB-101 was launched to support teachers, students, and the general public in PDB archive exploration (pdb101.rcsb.org). Maintained by the Research Collaboratory for Structural Bioinformatics PDB, PDB-101 aims to help train the next generation of PDB users and to promote the overall importance of structural biology and protein science to nonexperts. Regularly published features include the highly popular Molecule of the Month series, 3D model activities, molecular animation videos, and educational curricula. Materials are organized into various categories (Health and Disease, Molecules of Life, Biotech and Nanotech, and Structures and Structure Determination) and searchable by keyword. A biennial health focus frames new resource creation and provides topics for annual video challenges for high school students. Web analytics document that PDB-101 materials relating to fundamental topics (e.g., hemoglobin, catalase) are highly accessed year-on-year. In addition, PDB-101 materials created in response to topical health matters (e.g., Zika, measles, coronavirus) are well received. PDB-101 shows how learning about the diverse shapes and functions of PDB structures promotes understanding of all aspects of biology, from the central dogma of biology to health and disease to biological energy.

Conceptualizing learning about proteins with a molecular viewer in high school based on the integration of two theoretical frameworks

The use of a molecular viewer to visualize proteins has become more prevalent in high schools in recent years. We relied on the foundations of two theoretical frameworks to analyze questions in two learning tasks designed for 10th- to 12th-grade biotechnology majors that make use of Jmol. The two theoretical frameworks were: (i) classification of scientific knowledge into content, procedural, and epistemic knowledge; and (ii) evaluation of the cognitive skills central to visual literacy in biochemistry. During the analysis, two sub-elements of procedural knowledge emerged from the data: (i) the visualization of molecular models, and (ii) the use of Jmol software features. Based on the theoretical frameworks and data analysis, we suggest a conceptualization of learning about proteins using a molecular viewer, where the scientific knowledge elements are integrated with the eight cognitive skills central to visual literacy in biochemistry. In addition, a model presenting a hierarchy for the knowledge elements and sub-elements is suggested. In this model, content knowledge is a basic requirement; without it, the other knowledge elements cannot be used. Moreover, the use of epistemic knowledge or Jmol software features is not possible without visualization of the molecular models, which requires content knowledge. This conceptualization is expected to facilitate the development of learning tasks, decrease the complexity of knowledge acquisition for students; it may also assist the teacher during the teaching process.

Rejigging Electron and Proton Transfer to Transition between Dioxygenase, Monooxygenase, Peroxygenase, and Oxygen Reduction Activity: Insights from Bioinspired Constructs of Heme Enzymes

Nature has employed heme proteins to execute a diverse set of vital life processes. Years of research have been devoted to understanding the factors which bias these heme enzymes, with all having a heme cofactor, toward distinct catalytic activity. Among them, axial ligation, distal super structure, and substrate binding pockets are few very vividly recognized ones. Detailed mechanistic investigation of these heme enzymes suggested that several of these enzymes, while functionally divergent, use similar intermediates. Furthermore, the formation and decay of these intermediates depend on proton and electron transfer processes in the enzyme active site. Over the past decade, work in this group, using in situ surface enhanced resonance Raman spectroscopy of synthetic and biosynthetic analogues of heme enzymes, a general idea of how proton and electron transfer rates relate to the lifetime of different O2 derived intermediates has been developed. These findings suggest that the enzymatic activities of all these heme enzymes can be integrated into one general cycle which can be branched out to different catalytic pathways by regulating the lifetime and population of each of these intermediates. This regulation can further be achieved by tuning the electron and proton transfer steps. By strategically populating one of these intermediates during oxygen reduction, one can navigate through different catalytic processes to a desired direction by altering proton and electron transfer steps.

Protective Potential of Uric Acid, Folic Acid, Glutathione and Ascorbic Acid Against the Formation of Toxic Met-Myoglobin

BACKGROUND

Myoglobin is an oxygen binding protein and its dysfunction has been associated with the pathology of several human disorders. This study was undertaken to investigation the role of hydrogen peroxide (H2O2) in the formation of met-myoglobin and the protective potential of four different reductants such as uric acid, folic acid, glutathione and ascorbic acid were also tested against met-myoglobin formation.

METHODS

Human myoglobin was treated with H2O2 in-vitro in order to prepare met-myoglobin. The generation of met-myoglobin was confirmed by UV-visible spectroscopy and its stability was analysed by the treatment of human myoglobin with H2O2 at varying pH or time. High performance liquid chromatography (HPLC) was used to determine the oxidatively modified heme products in met-myoglobin. Spectroscopic analysis was used to identify the protective potential of uric acid, folic acid, glutathione and ascorbic acid against the formation of met-myoglobin.

RESULTS

The novel data of this study showed that H2O2 induced extensive damage of myoglobin but the treatment with uric acid, folic acid, glutathione or ascorbic acid provides protection of myoglobin against H2O2 induced oxidative damaged. The study apparently proved the protective potential of all these compounds against the toxicity produced by H2O2.

CONCLUSION

This is the first study that shows uric acid, folic acid, glutathione and ascorbic acid provide protection against the generation of toxic met-myoglobin and might be used therapeutically to modify the blood conditions in order to prevent the progression of human disorders associated with myoglobin dysfunction.

Iron deficiency without anaemia: a diagnosis that matters

Iron deficiency anaemia (IDA) currently affects 1.2 billion people and iron deficiency without anaemia (IDWA) is at least twice as common. IDWA is poorly recognised by clinicians despite its high prevalence, probably because of suboptimal screening recommendations. Diagnosing IDWA relies on a combination of tests, including haemoglobin and ferritin levels, as well as transferrin saturation. Although the causes of iron deficiency may sometimes be obvious, many tend to be overlooked. Iron sufficiency throughout pregnancy is necessary for maternal and foetal health. Preoperative IDWA must be corrected to reduce the risk of transfusion and postoperative anaemia. Oral iron is the first-line treatment for managing IDWA; however, intravenous supplementation should be used in chronic inflammatory conditions and when oral therapy is poorly tolerated or ineffective. This review considers the causes and clinical features of IDWA, calls for greater awareness of the condition, and proposes diagnostic and management algorithms.

Structural biology of tumor necrosis factor demonstrated for undergraduates instruction by computer simulation

This work presents a three-dimensional (3D) modeling exercise for undergraduate students in chemistry and health sciences disciplines, focusing on a protein-group linked to immune system regulation. Specifically, the exercise involves molecular modeling and structural analysis of tumor necrosis factor (TNF) proteins, both wild type and mutant. The structure of the tumor necrosis factor type 1 receptor (TNF-R1) is also briefly explored. TNF and TNF-R1 play major roles in maintaining human immune-system homeostasis. Upon binding with TNFR-1, the TNF can activate the nuclear factor kappa B (NF-κB), eventually resulting in apoptosis or cell death. These essential features of the clinically relevant TNF family is explored within the frame work of a readily adaptable tutorial. © 2015 by The International Union of Biochemistry and Molecular Biology, 44:246-255, 2016.