Active site cavity of herpes simplex virus proteases revealed by the crystal structure of herpes simplex virus protease/inhibitor complex.

Human herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) are responsible for Herpes Labialis (Cold Sores) and Genital Herpes, respectively. They encode a serine protease that is required for viral replication, and represent a viable target for therapeutic intervention. Here, we report the crystal structures of HSV-1 and HSV-2 proteases, the latter in the presence and absence of the covalently bound transition state analog inhibitor diisopropyl phosphate (DIP). The HSV-1 and HSV-2 protease structures show a fold that is neither like chymotrypsin nor like subtilisin, and has been seen only in the recently determined cytomegalovirus (CMV) and varicella-zoster virus (VZV) protease structures. HSV-1 and HSV-2 proteases share high sequence homology and have almost identical three-dimensional structures. However, structural differences are observed with the less homologous CMV protease, offering a structural basis for herpes simplex virus protease ligand specificity. The bound inhibitor identifies the oxyanion hole of these enzymes and defines the active site cavity.

Incidence of herpes simplex neonatorum in Netherlands

OBJECTIVE: Investigation of the incidence of neonatal herpes simplex in the Netherlands between 1992 and 1998. DESIGN: Inventory questionnaire survey. METHODS: All virological laboratories in the Netherlands were sent a questionnaire on the number of culture proven cases of neonatal herpes simplex recorded between 1992 and 1998 and on the type of herpes simplex virus (HSV-1 or HSV-2). The gynaecological and paediatric departments of all university hospitals and of half of the general hospitals were sent questionnaires as well. Gynaecologists were asked how often caesarean section was performed in order to prevent neonatal herpes simplex and how frequently pregnant women were seen with Genital Herpes. Paediatricians were asked how often they observed neonatal herpes, the type of HSV and the possible transmission route. Based on these data the figures for the whole of the Netherlands were estimated. RESULTS: The incidence of neonatal herpes simplex in the Netherlands in the period 1992 to 1998 was 2.4 per 100,000 neonates. HSV-1 was the cause of neonatal herpes simplex in 73%, HSV-2 in 9%, and in 18% of the cases the type of infection was not recorded. The number of pregnant women with genital herpes simplex had increased, but, in agreement with a consensus statement, the gynaecologists hardly performed caesarean sections any more to prevent neonatal herpes simplex (2 per year). CONCLUSIONS: The incidence of neonatal herpes simplex in the Netherlands had not increased. There was no predominant role of HSV type 2 causing neonatal herpes.

Screening for possible failure of herpes simplex virus PCR in cerebrospinal fluid for the diagnosis of herpes simplex encephalitis.

The objectives of this study were to evaluate the reliability of herpes simplex virus (HSV) PCR testing in cerebrospinal fluid (CSF) for the detection of herpes simplex encephalitis. This was done by examining retrospectively the clinical follow-up of a large group of patients tested routinely by HSV-PCR. In addition, an attempt was made to assess the incidence of herpes simplex encephalitis in a central European population. CSF samples from 1,427 patients from all Vienna hospitals were submitted for HSV-PCR testing during a period of 4 years and 8 months. Herpes Simplex encephalitis was detected by PCR in 12 cases and by serological methods in one additional patient. Retrospective analysis of the course of disease, which was possible in 799 PCR-negative patients, led to the identification of three additional cases in which herpes simplex encephalitis appears to have occurred despite negative PCR results. Failure of the PCR in these patients is most likely due to the time of obtaining CSF during the course of disease. A high specificity of the assay was demonstrated by the lack of false positive results in any of the 708 cases in which other causes for the neurological symptoms had been identified in the follow-up. The incidence of herpes simplex encephalitis in the population of Vienna was between 1 case/469,000-577,000 individuals/year. The highest annual incidence was detected in the age group between 3 months and 3 years, which, however, could not be confirmed statistically. Copyright 2001 Wiley-Liss, Inc.

Structure of replicating intermediates of human herpes simplex virus type 6.

We have studied the structure of the replicative intermediates of human herpes simplex virus 6 (HHV-6) using pulsed-field gel electrophoresis, partial digestion, two-dimensional gel electrophoresis, and sedimentation centrifugation. The results show that DNA replication of HHV-6 produces head-to-tail concatemeric intermediates as well as approximately equal amounts of circular monomers or oligomers. Unlike the situation in herpes simplex virus, the intermediates of human herpes simplex virus 6 replication are not highly branched, suggesting a difference in the mechanism of replication or a lower frequency of homologous recombination in human herpes simplex virus 6 compared to herpes simplex virus.