Chemical synthesis of a 28 kDa full-length PET degrading enzyme ICCG by the removable backbone modification strategy.

Chemical protein synthesis offers a powerful way to access otherwise-difficult-to-obtain proteins such as mirror-image proteins. Although a large number of proteins have been chemically synthesized to date, the acquisition to proteins containing hydrophobic peptide fragments has proven challenging. Here, we describe an approach that combines the removable backbone modification strategy and the peptide hydrazide-based native chemical ligation for the chemical synthesis of a 28 kDa full-length PET degrading enzyme IGGC (a higher depolymerization efficiency of variant leaf-branch compost cutinase (LCC)) containing hydrophobic peptide segments. The synthetic ICCG exhibits the enzymatic activity and will be useful in establishing the corresponding mirror-image version of ICCG.

Enhanced native chemical ligation by peptide conjugation in trifluoroacetic acid.

Chemical ligation of peptides is increasingly used to generate proteins not readily accessible by recombinant approaches. However, a robust method to ligate "difficult" peptides remains to be developed. Here, we report an enhanced native chemical ligation strategy mediated by peptide conjugation in trifluoroacetic acid (TFA). The conjugation between a carboxyl-terminal peptide thiosalicylaldehyde thioester and a 1,3-dithiol-containing peptide in TFA proceeds rapidly to form a thioacetal-linked intermediate, which is readily converted into the desired native amide bond product through simple postligation treatment. The effectiveness and practicality of the method was demonstrated by the successful synthesis of several challenging proteins, including the SARS-CoV-2 transmembrane Envelope (E) protein and nanobodies. Because of the ability of TFA to dissolve virtually all peptides and prevent the formation of unreactive peptide structures, the method is expected to open new opportunities for synthesizing all families of proteins, particularly those with aggregable or colloidal peptide segments.

Sperm-specific protein ACTL7A as a biomarker for fertilization outcomes of assisted reproductive technology / 亚洲男科学杂志(英文版)

Obtaining high-quality embryos is one of the key factors to improve the clinical pregnancy rate of assisted reproductive technologies (ART). So far, the clinical evaluation of embryo quality depends on embryo morphology. However, the clinical pregnancy rate is still low. Therefore, new indicators are needed to further improve the evaluation of embryo quality. Several studies have shown that the decrease of sperm-specific protein actin-like 7A (ACTL7A) leaded to low fertilization rate, poor embryo development, and even infertility. The aim of this study was to study whether the different expression levels of ACTL7A on sperm can be used as a biomarker for predicting embryo quality. In this study, excluding the factors of severe female infertility, a total of 281 sperm samples were collected to compare the ACTL7A expression levels of sperms with high and low effective embryo rates and analyze the correlation between protein levels and in-vitro fertilization (IVF) laboratory outcomes. Our results indicated that the ACTL7A levels were significantly reduced in sperm samples presenting poor embryo quality. Furthermore, the protein levels showed a significant correlation with fertilization outcomes of ART. ACTL7A has the potential to be a biomarker for predicting success rate of fertilization and effective embryo and the possibility of embryo arrest. In conclusion, sperm-specific protein ACTL7A has a strong correlation with IVF laboratory outcomes and plays important roles in fertilization and embryo development.

Prohibitin (PHB) interacts with AKT in mitochondria to coordinately modulate sperm motility / 亚洲男科学杂志(英文版)

Prohibitin (PHB), an evolutionarily conserved mitochondrial inner membrane protein, is highly expressed in cells that require strong mitochondrial function. Recently, we demonstrated that the deletion of Phb in spermatocytes results in impaired mitochondrial function. In addition, PHB expression in the mitochondrial sheath of human sperm has a significantly negative correlation with mitochondrial reactive oxygen species levels, but a positive one with mitochondrial membrane potential and sperm motility. These results suggest that mitochondrial PHB expression plays a role in sperm motility. However, the mechanism of PHB-mediated regulation of sperm motility remains unknown. Here, we demonstrate for the first time that PHB interacts with protein kinase B (AKT) and exists in a complex with phospho-PHB (pT258) and phospho-AKT in the mitochondrial sheath of murine sperm, as determined using colocalization and coimmunoprecipitation assays. After blocking AKT activity using wortmannin (a phosphatidylinositol 3-kinase [PI3K] inhibitor), murine sperm have significantly ( P < 0.05) decreased levels of phospho-PHB (pT258) and the total and progressive motility. Furthermore, significantly ( P < 0.05) lower levels of phospho-PI3K P85 subunit α+γ (pY199 and pY467) and phospho-AKT (pS473; pT308) are found in sperm from infertile asthenospermic and oligoasthenospermic men compared with normospermic subjects, which suggest a reduced activity of the PI3K/AKT pathway in these infertile subjects. Importantly, these sperm from infertile subjects also have a significantly ( P < 0.05) lower level of phospho-PHB (pT258). Collectively, our findings suggest that the interaction of PHB with AKT in the mitochondrial sheath is critical for sperm motility, where PHB phosphorylation (pT258) level and PI3K/AKT activity are key regulatory factors.

A controlled randomized trial of the use of combined L-carnitine and acetyl-L-carnitine treatment in men with oligoasthenozoospermia / 中华男科学杂志

<p><b>OBJECTIVE</b>To determine the efficacy and safety of combined L-carnitine and acetyl-L-carnitine therapy in infertile males with oligoasthenozoospermia.</p><p><b>METHODS</b>One hundred fifty patients with oligoasthenozoospermia were randomized selected into treatment and control groups. The treatment group with 90 patients were given L-carnitine (2 g/d) and acetyl-L-carnitine (1 g/d) orally, twice a day. The patients in control group were given Vitamin E 100 mg plus Vitamin C 100 mg, tid. The oral therapy lasted three months and patients accepted sperm analysis every one month. The L-carnitine level in seminal plasma was examined by high performance liquid chromatography (HPC). Side effects as well as pregnant rate were observed.</p><p><b>RESULTS</b>In the treatment group, 85 patients out of 90 finished the three month treatment. Female spouses of 10 patients (11.6%) achieved pregnancy. Moreover, their forward motile sperm per ejaculation, total motile sperm, as well as the concentration of L-carnitine in seminal plasma were increased significantly (P < 0.01). In control group, 53 patients out of 60 completed three months therapy. Two pregnancy (3.7%) was observed. Though some increase was seen in number of forward motile sperm and total motile sperm per ejaculation, the changes were not statistically significant (P > 0.05). The difference of the pregnant rate between two groups was statistically significant. No side effects were found.</p><p><b>CONCLUSION</b>Combined treatment with L-carnitine and acetyl-L-calmitine can be an effective and safe option for treating oligoasthenozoospermia by means of significantly improving forward motile sperm and total motile sperm per ejaculation, as well as increasing pregnant rates.</p>